Updated Oct 17

The Fortress Belt

Russia’s commanders claim the Fortress Belt’s southern cities; the evidence does not show them taken.

On October 16 Russia’s chief of general staff, Valery Gerasimov, told Putin his forces had captured Dobropillya, Kostiantynivka and Oleksiievo-Druzhkivka, entered Druzhkivka and reached the outskirts of Kramatorsk. ISW calls the claims false. It sees only limited infiltration in Dobropillya and puts Russian troops, infiltrators included, at least 9 kilometres from Kramatorsk and 12 from Druzhkivka. Ukraine’s General Staff and the Azov corps say Dobropillya and the villages around it remain Ukrainian, and a Russian military blogger conceded that no advance into the town’s centre is confirmed. DeepState does show a small Russian advance near Svitle, beside it.

Kostiantynivka is where the fighting is real. Russian troops have infiltrated much of its south and centre without consolidating them, and are now working north of the city around Novodmytrivka and Molocharka, on an observer’s account ISW accepts. Ukrainian troops still hold positions inside it.

In the north, the Russian salient at Lyman stays collapsed after Operation Vivaldi, and ISW assesses that Ukrainian forces held or advanced east of Slovyansk and Kramatorsk.

New Oct 17

The whole story5 chapters

The state of it — as of October 17, 2026

17 km+

between Russian lines and Slovyansk after the Lyman salient collapsed

9 km+

between Russian troops, infiltrators included, and Kramatorsk (ISW)

38%

of Kostiantynivka Russian forces have advanced into, without taking it (ISW)

Today

NewOct 17, 2026

Moscow Announces Dobropillya and the Edge of Kramatorsk. ISW Puts Its Troops 9 Kilometres Away.

On October 16 Russia’s chief of general staff told Putin his forces had taken Dobropillya and Kostiantynivka and reached Kramatorsk; the Defence Ministry repeated the list a day later. ISW calls the claims false. It sees only limited infiltration in Dobropillya, where a Russian military blogger conceded that no advance into the centre is confirmed, and puts Russian troops, infiltrators included, at least 9 km from Kramatorsk and 12 km from Druzhkivka. Ukraine’s General Staff and Azov say Dobropillya and nearby villages remain Ukrainian. DeepState shows a small Russian advance near Svitle, by Dobropillya.

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Institute for the Study of WarInstitute for the Study of WarUkrinformUkrainska PravdaNV (Novoye Vremya)The Moscow TimesKyiv PostUA.NEWS

NewOct 17, 2026

Russian Infiltrators Work North of Kostiantynivka Without Holding It

Russian forces have infiltrated north of Kostiantynivka, ISW assessed. The Ukrainian military observer Kostyantyn Mashovets reports them operating in Novodmytrivka, trying to advance from Molocharka, and holding ground between Panfilova Street in the city’s north-west and the Kryvyi Torets river; none of it is geolocated. A day earlier ISW assessed that Russian troops had infiltrated much of the south and centre without consolidating it, and had seen none in the north. Ukraine’s General Staff says its troops still hold positions in the city. ISW judges that resistance there is keeping Russia from pushing on to Druzhkivka and Kramatorsk.

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Institute for the Study of WarInstitute for the Study of WarUkrainska Pravda

NewOct 16, 2026

Russian forces have seized Kostiantynivka, Oleksiievo-Druzhkivka, Dobropillya, Pervomaiske and Serhiivka, have entered south-eastern and south-western Druzhkivka, have reached the outskirts of Kramatorsk, and control half of Mykolaivka, east of Slovyansk.

— Valery Gerasimov False

Checked: false

False. ISW sees no Russian consolidation in Dobropillya or Oleksiievo-Druzhkivka, observed Ukrainian troops in western Kostiantynivka on October 10, and puts Russian forces, infiltrators included, at least 9 km from Kramatorsk and 12 km from Druzhkivka. On Mykolaivka, Kyiv concedes only a small infiltration group.

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Institute for the Study of WarInstitute for the Study of WarUkrainska PravdaThe Moscow Times

Oct 15, 2026

Russia Presses Dobropillya Before Winter

Russian forces mounted a motorised assault toward Dobropillya and are intensifying attacks there ahead of winter, ISW assessed on October 15; a Ukrainian brigade spokesperson says the aim is to hold the town’s outskirts. ISW calls Dobropillya critical to what remains of Moscow’s plan: the southern arm of a wide encirclement of the Fortress Belt, cutting Ukrainian supply lines, and cover for the western flank of a push on Kramatorsk. In the south, a Ukrainian corps spokesperson reports Russia massing troops and armour near Hulyaipole with, reportedly, a five-to-one manpower edge — a claim ISW does not verify.

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Institute for the Study of WarInstitute for the Study of WarInstitute for the Study of War

Earlier this month

Oct 14, 2026

Vivaldi Reaches Kolodyazi, and the Northern Arm Stays Gone

Ukrainian troops retook Kolodyazi, Lypove and Zelena Dolyna north of Lyman, and ground near Stavky and Shandryholove, in the fourth phase of Operation Vivaldi; DeepState also shows the three villages liberated. ISW assessed on October 14 and 15 that it has collapsed the Russian salient north of Lyman, ending Moscow’s plan to encircle the Fortress Belt from the northwest. Its effects now reach the Borova direction and east of Slovyansk, where Russia’s Southern Grouping has slowed its attacks. The corps’ own totals for the operation — 277 square kilometres and 16 settlements — have not been independently confirmed.

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Ukrainska PravdaUkrainian News Agency (Ukranews)Institute for the Study of WarInstitute for the Study of War

Oct 14, 2026

Operation Vivaldi’s fourth phase liberated a further 101 square kilometres, for 277 square kilometres and 16 settlements over four phases. “We have prevented the enemy from bypassing the Sloviansk-Kramatorsk urban agglomeration from the flanks and encircling it, while also protecting the Kharkiv-Sloviansk motorway… We have disrupted the offensive by Russia’s Zapad (West) Group of Forces and forced it to redeploy some units of the 1st Guards Tank Army, easing the pressure on Kupiansk-Vuzlovyi.”

— Andrii Biletskyi

Not yet checked

Unverified. DeepState corroborates the three villages named in the phase; no tracker has published an area figure for it, and ISW reports the 101 and 277 square-kilometre totals without confirming them. ISW says the tank-army move matches its own forecast but gives no position.

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Ukrainska PravdaInstitute for the Study of War

Oct 9, 2026

Moscow Announces Kostyantynivka Again. ISW Sees Russian Troops in 38 Percent of It.

Russia’s Defence Ministry repeated on October 9 its claim to have seized Kostyantynivka, first made in early July. ISW assesses that Russian forces had advanced within 37.88 percent of the town as of October 6, have not consolidated many of the positions they infiltrated, and have not taken it; Ukrainian forces hold the north and northwest. Geolocated footage confirmed Russian advances in the town’s northwest on September 18 and October 4. ISW says the defence appeared to be stabilising at the end of September, and that Russia is planning its move on Druzhkivka as though the town were already held.

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Institute for the Study of WarInstitute for the Study of WarInstitute for the Study of WarInstitute for the Study of War

Oct 9, 2026

A New Russian Drone Regiment at Lyman — Reported, Not Located

Ukrainian military intelligence reported on October 9 that Russia’s 71st Separate Unmanned Systems Forces Regiment is operating in the Lyman direction — the first evidence ISW has seen of the unit in Ukraine. The report gives a direction, not a position, and no footage places it. A Ukrainian official said on October 7 that Russia is moving drone and Spetsnaz units from quieter sectors toward Slovyansk and Kramatorsk, and a Russian source said fresh regiments are due north of Lyman before winter to relieve two worn-down ones. ISW assesses the two Russian armies around Lyman as likely very degraded.

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Institute for the Study of WarInstitute for the Study of WarInstitute for the Study of War

Oct 8, 2026

ISW: Ukraine Has Defeated Russia’s 2026 Campaign for Donetsk

In a special report on October 8, ISW concluded that Ukraine has defeated Russia’s 2026 campaign to seize Donetsk Oblast. The plan, as ISW reconstructs it, was a deep encirclement of the whole Fortress Belt: one arm through Lyman, another north from Dobropillya, meeting near Barvinkove. Operation Vivaldi collapsed the Lyman salient and with it the northern arm. Russian lines there are at least 17 kilometres from Slovyansk. The southern arm continues, and no Fortress Belt city has fallen. Russia seized 630.37 square kilometres of Donetsk in the year to October 1; 5,382 remain. Putin has reportedly moved his deadline from the end of 2026 to spring 2027; ISW calculates his deadline would need more than 45 square kilometres a day. ISW’s own caveats: this is not a defeat on the scale of Kharkiv in 2022, the long-term implications are unclear, and the threat to Kostyantynivka is not over.

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Institute for the Study of WarEuronewsInstitute for the Study of War

Oct 8, 2026

Russian forces may continue to make slow creeping advances in the Fortress Belt but will fail to meet Putin’s newly revised deadline of seizing all of Donetsk Oblast by Spring 2027, if they can seize it at all.

— Institute for the Study of War

Not yet checked

Recorded as a prediction resolving 31 May 2027, the latest reading of “spring”. When it was made, ISW counted 5,382 square kilometres of Donetsk Oblast still outside Russian control and no Fortress Belt city taken.

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Institute for the Study of War

Oct 8, 2026

Russian Bloggers Concede Ground East of Slovyansk and Kramatorsk

Russian military bloggers acknowledged that Ukrainian forces retook Ozerne and Malynivka, drove Russian troops from Pyskunivka and advanced toward Kryva Luka and north of Rai-Oleksandrivka. Geolocated footage published October 8 shows Russian shelling of Ukrainian positions on the south bank of the Siverskyi Donets near Pyskunivka — evidence that Ukrainian troops have crossed the river. ISW says the counterattacks could disrupt Russia’s drive on Slovyansk from the east, while cautioning that positions east of Kramatorsk remain intermixed. Rai-Oleksandrivka is disputed: a Ukrainian commander called it cleared on September 19; a Russian blogger had Ukrainian troops still approaching it on September 28.

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Institute for the Study of WarInstitute for the Study of WarInstitute for the Study of WarInstitute for the Study of WarInstitute for the Study of War

Sep 28, 2026

Vivaldi’s Third Phase: 176 Square Kilometres Claimed, at Least 147 Assessed

Ukraine’s 3rd Army Corps announced a third phase of Operation Vivaldi on September 28: 51 more square kilometres and five villages north of Lyman — Nove, Ridkodub, Katerynivka, Karpivka and Novomykhailivka — for 176 in all. A second phase, announced September 20, had named Shandryholove and Derylove. The figures are the corps’ own. ISW’s assessment is at least 147 square kilometres liberated, and it says the operation has gone further than official Ukrainian reporting shows; Russian military bloggers describe Ukrainian troops pushing toward the Zherebets River. President Zelensky gave a lower range on October 3: 125 to 140.

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Institute for the Study of WarThe Kyiv IndependentInstitute for the Study of WarInstitute for the Study of WarEuronews

Sep 17, 2026

What Vivaldi Was For: a Pincer That Was Supposed to Close at Barvinkove

Biletskyi said the operation broke a Russian design to encircle the Donetsk Fortress Belt with two pincers — north through Lyman and Svyatohirsk, south through Dobropillya — meeting at Barvinkove, and that the northern arm has been operationally defeated. A battalion commander said his troops entered Serednie with armour after fitting tanks to cross rain-softened ground the Russians had judged impassable. A deputy commander said attempts to retake it failed, and that Russian channels called the footage AI-altered. This is the attacking side’s account of its own operation; ISW has not confirmed it.

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Institute for the Study of WarInstitute for the Study of War

This quarter

Sep 15, 2026

The Lyman Counteroffensive Has a Name, and 85 Square Kilometres

Ukraine’s counteroffensive against the Russian salient north of Lyman was publicly confirmed for the first time on September 15 and named: Operation Vivaldi. Brig. Gen. Andrii Biletskyi of the 3rd Army Corps put the ground cleared or liberated at 85 square kilometres, including the settlement of Serednie, with Russian infiltrators cleared from Novoselivka, Yarova, Oleksandrivka and the outskirts of Korovii Yar, and said this was only the first phase. ISW assesses Ukraine likely gained more than he reported: a Russian milblogger conceded that Russian forces are trying to push Ukrainians out of Kolodyazi, and geolocated footage shows Russian artillery shelling positions there — an admission against interest that ISW reads as Ukrainian liberation of the village.

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Institute for the Study of WarInstitute for the Study of War

Sep 6, 2026

Russian propaganda outlets continue to spread false reports about the alleged 'capture' of Sviatohirsk and are attempting to back them up with staged materials. In reality, Sviatohirsk remains under Ukrainian control.

— Donetsk Regional Military Administration Mixed

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UkrinformInstitute for the Study of WarInstitute for the Study of War

Sep 2, 2026

Ukraine's Counteroffensive Turns the Russian Salient at Lyman

The intensified Russian push toward Lyman that was building in late August has instead run into a Ukrainian counteroffensive. Across 28 August to 2 September Ukrainian forces cleared Russian infiltrators from a string of villages northwest of Lyman — Novoselivka, Yarova, Pryshyb, Tetyanivka, Oleksandrivka and Svyatohirsk — advanced in northern Novoselivka, liberated strongholds near Katerynivka and Stavky, and worked to cut off the Russian salient jutting northwest of the town. Russian sources themselves conceded that Ukrainian forces hold central Lyman and that Russia has no significant presence there, and that its claims to nearby Ozerne and Dibrova, announced captured months ago, do not match the ground. East of Slovyansk, Ukrainian troops captured Russian soldiers while clearing Mykolaivka. ISW says its 129.81-square-kilometre figure for August understates these gains, whose full extent is still unclear; the Serebrianskyi forest's minefields are slowing the Russians further.

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Institute for the Study of WarInstitute for the Study of WarInstitute for the Study of WarTexty.org.ua

Sep 1, 2026

Slovyansk Comes Under Artillery Fire as Russia Readies a Direct Assault

Russia moved its attack on Slovyansk into a new phase. The head of the city's military administration, Vadym Lyakh, said on 1 September that Russian forces are now seven to ten kilometres away and within artillery range, shelling the city with tube guns rather than only rockets, and ISW recorded the 123rd Separate Motorized Rifle Brigade redeploying from Siversk to reinforce the push. Before any direct assault, ISW and Ukrainian analysts say Russia must first take the fortified buffer villages of Rai-Oleksandrivka and Mykolaivka. Observer Kostyantyn Mashovets judges Russian forces could reach the immediate approaches of Slovyansk and Kramatorsk by the autumn, while doubting they can seize either city, or close an encirclement, before the year ends.

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Institute for the Study of WarInstitute for the Study of WarInstitute for the Study of War

Aug 29, 2026

A Third of the Force Massing for Lyman Is Foreign

A Ukrainian brigade spokesman on the Sloviansk axis said Russian forces are accumulating personnel and equipment for an intensified push in the Lyman direction, and that foreign recruits — mainly from Latin America, Africa and Southeast Asia — have risen to roughly 30 percent of Russian personnel there, poorly trained. Russian strikes are concentrating on Ukrainian logistics and the Oskil and Siverskyi Donets crossings, which ISW reads as shaping. Two days earlier Russian effort east of Sloviansk had shifted onto Mykolaivka and Raihorodok, the settlements ISW names as prerequisites for a ground assault.

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Institute for the Study of WarInstitute for the Study of War

Aug 27, 2026

Russian forces have seized Pyskunivka, Pershomarivka and Orikhuvatkha, stand four kilometres from the eastern outskirts of Sloviansk and are fighting three kilometres from Kramatorsk; they occupy almost half of Oleksiievo-Druzhkivka, are 1.5 kilometres from Druzhkivka, and seized more than 100 square kilometres in the Druzhkivka area alone in July and August 2026.

— Valery Gerasimov False

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Institute for the Study of War

Aug 26, 2026

Kostiantynivka's Defenders Fall Back Across the River, and Slovyansk Starts Getting the Same Treatment

Ukrainian forces pulled their main body out of southeastern Kostiantynivka to the eastern bank of the Kryvyi Torets, holding the north and northwest while individual units still operate in the centre. Russian lead elements — small infantry groups, the main body not yet committed — reached the Central Market on Bakhmutska Street, took Illinivka to the southwest, and pushed north through Novodmytrivka to Stinky to work around the defenders. Russia has been trying to take the city for ten months and claimed it captured on 5 July. Fifty kilometres north, the same method is being prepared against Slovyansk: Smerch and Tornado-S launchers have joined the glide bombs, five bombs fell on the morning of 26 August damaging 13 residential buildings, and the intent is to rubble the city before infantry enter. ISW puts Rai-Oleksandrivka and Mykolaivka in the way first.

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Institute for the Study of War

Aug 23, 2026

Russia Finds a New Door to Slovyansk

After a fortnight in which the front barely moved, Russia opened a different approach to the Fortress Belt. ISW assessed on August 23 that Russian forces advanced east of Sloviansk, consolidating Zakitne and Kryva Luka on the southern bank of the Siverskyi Donets and reaching the south-eastern outskirts of Pyskunivka — bypassing the northern route through Lyman that Ukrainian defences and river lines have held since spring. A Ukrainian brigade near Pokrovsk reported Russian reserves massing for a resumed push on Dobropillya, which ISW reads as the encirclement's southern arm. ISW still calls rapid gains west of Mykolaivka extremely unlikely.

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Institute for the Study of WarInstitute for the Study of WarInstitute for the Study of WarInstitute for the Study of War

Aug 8, 2026

The Fortress Belt Push Stalls as Ukraine Holds Lyman

For all the emphasis on the Pokrovsk and Dobropillya axes, the ground barely moved. Across August 6 to 8 ISW recorded no confirmed Russian advances in the Pokrovsk, Dobropillya or Kostiantynivka–Druzhkivka directions, with Ukrainian forces counterattacking in each — holding and pushing out from Osykove north-west of Kostiantynivka, retaking part of Muravka north-east of Novopavlivka, and advancing again north-east of Oleksandrivka around Zirka. North of Sloviansk, where Russia has been trying to cross the Seversky Donets and infiltrate toward Lyman, Ukrainian troops continued to hold western Lyman, Yampil and Zarichne, and Russian milbloggers themselves conceded that a string of settlements south-east of Borova now sit outside the Russian forward edge. DeepState logged Russia's only confirmed capture of the week to August 6 as Sukhetske, a village near Dobropillya, and recorded no Ukrainian gains in the same window — a reminder that a stalled Russian offensive is not the same thing as a Ukrainian advance. Behind the slowdown, Ukraine's Unmanned Systems Forces commander, Robert "Magyar" Brovdi, reported that the daily rate at which his units were detecting and eliminating Russian troops fell 16.3 percent between July and early August, from 374 to 313 a day, which he attributed to heavy Russian losses in breakthrough attempts and strained Russian logistics in the south.

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Institute for the Study of WarInstitute for the Study of WarRussia Matters

Aug 3, 2026

Russia Opens a Glide-Bomb Campaign to Isolate the Fortress Belt

The Institute for the Study of War assessed that Russia has begun a 2026 battlefield air interdiction (BAI) campaign against Ukraine's Fortress Belt — the chain of Donetsk cities anchored by Slovyansk and Kramatorsk — using glide bombs to sever the logistics that sustain the defence rather than assaulting the cities head-on. Geolocated footage from August 2 showed a rocket-artillery strike heavily damaging the Cherivkovsky Bridge over the Kazennyi Torets River in eastern Slovyansk, a crossing that feeds the H-20 highway to Kramatorsk. ISW reads the effort as a repeat of the interdiction that preceded the 2025 fights for Pokrovsk and Hulyaipole — a shaping operation that took months to set conditions — and judges that Russian forces are nonetheless unlikely to advance quickly to or through Slovyansk and Kramatorsk. In the same window Russian infiltrators near Kostiantynivka began moving north toward Oleksiievo-Druzhkivka, and Russia attempted to infiltrate Lyman, north-east of Slovyansk, though ISW saw no evidence its forces had entered the town.

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Institute for the Study of War

Jul 29, 2026

The Front Moves Again, and It Moves Inside Kostiantynivka

After four days in which ISW recorded no confirmed advance by either side anywhere on the front, geolocated footage put Russian forces forward in western Kostiantynivka on 28 July. ISW's assessment that day: the situation in the city is deteriorating, Russian forces have not seized it despite their claims, and fighting will likely continue for several weeks as they try to consolidate what infiltration has gained. It named the mechanism — glide bombs enabling infantry advances — and the four cities taken the same way: Avdiivka, Vuhledar, Kurakhove, Toretsk. DeepState put the stake more sharply: if Novodmytrivka falls, the Ukrainian grouping defending Chasiv Yar faces encirclement. Ukrainian soldiers told Hromadske the rear was not at risk for several more weeks, while conceding Molocharka was essentially lost.

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Institute for the Study of WarInstitute for the Study of WarInstitute for the Study of WarEuromaidan Press

Jul 22, 2026

Dobropillya Becomes the Active Axis

Ukrainian military observer Kostyantyn Mashovets reported on 22 July that Russian forces had reached the Rodynske–Novooleksandrivka line south of Dobropillya, likely seizing Novooleksandrivka, with elements of the 2nd, 41st and 51st Combined Arms Armies pushing toward the town — including three separate rifle regiments ISW had never before observed in the field. The aim, he assessed, was to take Dobropillya quickly and open a path to Druzhkivka and the Fortress Belt. ISW relayed the account as likely rather than geolocated, so no map polygon moved on it. The axis did not open: ISW recorded no confirmed Russian advance there on 23, 24, 25 or 26 July, and by 29 July a Kremlin-affiliated blogger was reporting Ukrainian counterattacks near Svitle and Vodyanske.

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Institute for the Study of WarInstitute for the Study of WarInstitute for the Study of WarInstitute for the Study of WarInstitute for the Study of WarInstitute for the Study of War

Jul 22, 2026

ISW Revises Kostyantynivka Assessment Toward Ukrainian Control

The Institute for the Study of War restated its control assessment for Kostyantynivka on 22 July, against the direction Russian commanders had claimed. From geolocated footage published 11-21 July, ISW assesses control of the city is still contested: Russian forces infiltrating the northwest, centre, east and southwest, Ukrainian forces holding positions in the northwest, northeast and centre and more of the southern industrial area than ISW previously judged. Its point is definitional — infiltration is not control, so the city has not changed hands. By 26 July nothing had moved Russia's way, and DeepState, counting differently, agreed: Russia held the southern and eastern outskirts while the neighbourhoods stayed mostly grey zone and the north stayed Ukrainian. No Russian claim of capture appears in the 24, 25 or 26 July assessments.

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Institute for the Study of WarInstitute for the Study of WarInstitute for the Study of WarInstitute for the Study of WarInstitute for the Study of WarInterfax-Ukraine

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