Ukraine’s Security Service (SBU) detained two men suspected of scouting targets for Russian strikes on Sloviansk and Dnipro, the agency reported on 14 October. Catching both early let it secure Ukrainian reserve command posts and the gas stations the alleged agents had been hunting, the agency added.

Sloviansk anchors the northern end of the Fortress Belt, the chain of fortified cities that has held Ukraine’s defense of Donetsk Oblast since 2014. Russia is pushing to seize them, and its aircraft bombed a residential area of Sloviansk on 11 October. Where Ukrainian convoys stop and troops gather is exactly what Russian handlers allegedly asked these suspects to supply.

A gas station worker suspected of filming convoys

The first suspect worked at a gas station complex in Sloviansk, Donetsk Oblast. Russian intelligence allegedly reached him through a former classmate who left for Russia after the full-scale invasion and now works for its special services, the SBU said. He then allegedly used his phone to secretly film Ukrainian army convoys at or near gas stations. He was allegedly supposed to send the photos and videos to Russia to help it prepare a targeted strike. He also allegedly drove his own car around other gas stations and bridges that the Defense Forces use for logistics.

Spotted through Telegram comments

The second suspect, a former Pokrovsk resident, moved to Dnipro in 2024 and settled in a dormitory. Russian intelligence noticed him through pro-Kremlin comments he posted in Telegram chats, investigators say. A female handler in Russia allegedly tasked him with guiding missile and drone attacks on places in the city where Ukrainian troops and equipment were concentrated. He allegedly scouted on foot or took public transport to reach outlying districts.

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Officers seized computers and smartphones containing evidence of the men’s alleged work for Russia. Both are suspected of treason under martial law and of unauthorized dissemination of information on Ukrainian troop movements or deployment, under Articles 111(2) and 114-2(2) of the Criminal Code. They remain in custody without bail and face up to life imprisonment with confiscation of property. The SBU’s office for Donetsk and Luhansk oblasts ran the operation under the Donetsk Oblast Prosecutor’s Office.

A Russian attack on Sloviansk on 13 October wounded members of a Ukrainian Red Cross team, the Ukrainian Red Cross Society reported. The same day, a Russian bomb hit the city’s invincibility point, one of the state-run hubs where residents warm up and charge phones when power goes out.

Help is getting harder to reach in Sloviansk. Public transport stopped after a Russian strike on two buses in nearby Kramatorsk killed 30 people on 8 October. From 1 November, a curfew from 16:00 to 11:00 will cover nearly all of Donetsk Oblast’s free territory. The people providing help are hit too. Russian drones struck three ambulances in Kramatorsk on 5 October. In August, a Russian strike destroyed a World Health Organization humanitarian warehouse in Dnipro.

Team had moved from Lyman

Three members of the society’s Lyman city branch were hurt. The branch had moved to Sloviansk because of the security situation and kept working there. All three were hospitalized with shrapnel wounds and burns. The building where the team worked took heavy damage, and a fire caused by the attack damaged the organization’s property.

The society’s Donetsk Oblast branch later added that a fourth person suffered a concussion, and that all four were hospitalized. The Red Cross condemned attacks on civilian infrastructure and humanitarian workers.

Bomb hit the warming center

The strike came at 12:45 in the Lisnyi microdistrict, Sloviansk city military administration head Vadym Liakh wrote. He later identified the weapon as a FAB-250, a 250-kg air-dropped bomb. Eight people were injured, and five apartment blocks were damaged, Liakh said. He described the warming center’s building as damaged, while Suspilne Donbas reported it destroyed.

Two Russian strikes on Sloviansk that day killed at least one person, Donetsk Oblast head Vadym Filashkin wrote. Liakh said a Russian attack on the Semenivka neighborhood killed a 55-year-old woman. On 14 October, Filashkin reported that Russian attacks killed three people across Donetsk Oblast on 13 October, in Sloviansk, Druzhkivka, and Starovarvarivka.

Ukrainian forces are advancing east of Sloviansk and Kramatorsk, and even Russian milbloggers now acknowledge it, the Institute for the Study of War (ISW) said on 8 October. The gains may follow months of groundwork like the one that preceded Operation Vivaldi near Lyman, which Ukraine says returned 176 km² to its control. Russian commentators are already doubting that Moscow can reach the two cities.

Russia's years-long push on the Fortress Belt, the chain of cities anchoring Ukraine's defense in Donetsk Oblast, has been stalling since Vivaldi began. Unable to take those cities, Russia keeps hitting them from the air. On 8 October, a Russian bomb killed 30 people on two buses in Kramatorsk.

Across the Siverskyi Donets

Russian milbloggers said Ukrainian forces liberated Ozerne and advanced east of Pyskunivka toward Kryva Luka, ISW reported. They also acknowledged that Ukrainian troops drove Russian forces out of Pyskunivka. Ukrainians are now counterattacking toward Kryva Luka from the west and northwest, from across the river.

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ISW called the repeated Russian claims of a river crossing notable, because the Siverskyi Donets is a significant natural obstacle. Kryva Luka is a dominant height just south of the river. From there, Ukraine could launch further counterattacks. Ukrainian forces appear to have pushed Russian troops off both banks in this area, ISW assessed.

The heights Russia wanted

After Vivaldi cleared ground near Lyman in September, Russia shifted its push south toward Mykolaivka and Sloviansk. Russian forces likely see Mykolaivka, just east of Sloviansk, as a primary objective, ISW said. Its heights would favor an offensive on the city. Ukrainian pushes northeast and southeast of the town now deny Russia that terrain.

East of Kramatorsk, milbloggers claimed Ukrainians liberated Malynivka and advanced between Fedorivka Druha and Holubivka. They also reported gains into southern Minkivka and near Fedorivka. The lines remain tangled. Geolocated footage shows Ukrainian forces striking a Russian position in central Tykhonivka after what ISW assesses was a Russian infiltration.

ISW said the counterattacks may point to a broader Ukrainian goal: pushing Russian forces east, away from the Sloviansk–Kramatorsk area and toward the Siverskyi Donets–Donbas Canal.

The Vivaldi playbook

The counterattacks have run for weeks. On 29 September, Ukrainian military observer Kostiantyn Mashovets reported them in the same areas, saying Russia's 3rd Combined Arms Army had failed to make significant gains. ISW assesses that the attacks build on months of shaping meant to wear down Russia's offensive capacity.

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Before Vivaldi, Ukrainian forces targeted Russian drone operators, gaining drone superiority before the counteroffensive. They used the same approach ahead of their Oleksandrivka counterattacks in early 2026.

Moscow appears to see the pattern. A Ukrainian military official said on 7 October that Russia is moving drone units and Spetsnaz from quieter sectors to the Sloviansk–Kramatorsk direction. Ukraine also reorganized its command in and around Donetsk Oblast in early September, which may be blunting Russian attacks from the east, ISW said.

"Distant" and "doomed"

One Russian milblogger called an advance toward the Sloviansk–Kramatorsk area a "distant" prospect, ISW reported. A Russian offensive from Siversk toward Sloviansk may be "doomed" to failure or heavy losses unless Russia retakes the forests south of Lyman, he said.

The counterattacks east of the two cities appear to support Vivaldi, ISW assessed. Together with Russia's defeat north of the river, they could disrupt Russia's offensive toward Sloviansk from the east entirely.

If Ukraine holds Kryva Luka and keeps Russia off the Mykolaivka heights, Moscow's pincer on Sloviansk and Kramatorsk loses the ground it was built on.

Russian forces struck the eastern Ukrainian city of Kramatorsk on the morning of 8 October, hitting two route buses carrying residents and killing dozens of civilians. The Donetsk Oblast prosecutor's office opened a war-crimes investigation.

Russia has turned everyday movement in frontline Donetsk Oblast into a lethal risk, striking city buses, ambulances, and cars in places its army has not been able to capture.

A route bus run turned deadly

The attack came at around 10:00, catching two route buses in the impact zone. The prosecutor's office said the attackers likely used a UMPB D-30SN. HUR, Ukraine's military intelligence, describes it as a guided glide bomb that can fly up to 100 km when released from an altitude of 12–15 km and carries a warhead equal to a FAB-250 aerial bomb.

The toll rose through the day, from 12 dead in the first reports to 30 killed and 20 wounded by 14:55, Donetsk Oblast head Vadym Filashkin said. Across Donetsk Oblast, Russian attacks killed 33 people that day, including the 30 in Kramatorsk and three in nearby Bilenke, the State Emergency Service said. Ukrainian President Volodymyr Zelenskyy said the strike would not go unanswered.

Buses pulled off the roads

Filashkin ordered the Kramatorsk and Sloviansk city military administrations to suspend public transport, citing the sharp deterioration in security. Buses had become an attractive target for Russian forces, he said, and the authorities could not risk the lives of passengers and drivers. He also urged everyone still in Donetsk Oblast to leave for safer parts of Ukraine. Kramatorsk is a frequent target of Russian attacks. Russia had not commented on the strike as of publication.

The city has been under daily fire. On 5 October, Russian FPV drones hit ambulances and an apartment block in Kramatorsk, killing a woman and wounding four, the prosecutor's office reported. Over the previous day, Russian forces shelled Donetsk Oblast settlements 31 times and 256 people left the front line, Filashkin said.

Russia lost almost 300 km² of Ukrainian territory on net between March and September 2026, and it likely gained no ground in September despite its heaviest casualties of the year, the Institute for the Study of War (ISW) assessed. Ukraine's Operation Vivaldi accounts for much of the swing. The think tank notes that Ukraine's secrecy around such counterattacks makes exact monthly tallies hard.

Russia has pressed attacks along the entire front through 2026, accepting mass casualties for marginal ground, and its battlefield year has already been called its worst since 2023. Its losses have been outpacing its recruitment for months.

Russia came out behind in September

Russian forces seized 175.54 km² in September but lost 256.35 km², a net loss of 80.81 km², or minus 2.69 km² a day, ISW calculated. The balance stayed negative when Russian infiltrations into areas Russia does not control are counted: Russia seized or infiltrated 143.2 km² but lost 318.38 km², a net loss of 175.18 km².

The September figures include at least 147 km² near Lyman that Ukraine liberated over earlier months, but that ISW recorded only once details of Operation Vivaldi emerged in September. The operation already disrupted Russia's plan to encircle the Fortress Belt cities from the Lyman and Dobropillia directions.

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Almost 300 km² lost since March

Russia's rate of seizing territory dropped sharply in March 2026 and has stayed low, or even negative, since, ISW found. After controlling for the gains Ukraine made during Vivaldi, Russia lost control of 293.59 km² net across the front since March. Counting infiltrations, it gained a presence in only 174.44 km² over the same period.

ISW's monthly chart shows net Russian losses of 116.01 km² in April and 281.1 km² in May, modest gains in June, July, and August, and a net loss again in September. Oleksandr Syrskyi, then Ukraine's commander-in-chief, reported in June that Ukrainian forces had recaptured 100 km² in May.

More than 46,000 casualties for no ground

Russian forces suffered 46,230 casualties in September, Ukraine's General Staff reported. It is the third straight month above 40,000 and the highest monthly toll of 2026, by Kyiv's count. Monthly Russian casualties have climbed from 32,980 in April to 42,860 in July and 42,020 in August, ISW's chart shows.

Russia keeps suffering heavy personnel losses while making extremely limited or even net-negative territorial gains, ISW said, and its current force generation system still recruits fewer soldiers than it needs to replace them.

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Ukraine's effective operational security around Vivaldi, likely to continue in future counterattacks, will make meaningful month-to-month assessments of Russian gains and losses hard, the think tank added.

The Institute for the Study of War (ISW) published a map in its analytical report on 24 September that contrasts the claimed Russian encirclement with the location of Russian forces as assessed by the experts. Based on the evidence observed by ISW, the nearest area where Russian forces are present is 10.2 kilometers from the southeastern outskirts of Dobropillia.

Russia has been spreading disinformation about its successes around Dobropillia as part of what ISW calls a cognitive warfare effort to portray Ukrainian defenses as on the verge of collapse. Russia's Defense Ministry published a map claiming the city was surrounded. ISW's own map challenges it. The Ukrainian military says the city remains under its control.

Russian Defense Ministry claims it is already destroying encircled Ukrainian troops in Dobropillia and moving further

Units of Russia's Center Grouping of Forces continue combat operations against encircled Ukrainian forces in the Dobropillia area of Donetsk Oblast while simultaneously advancing toward Oleksandrivka, the Russian Defense Ministry claimed. ISW analysts, meanwhile, said they have not observed evidence supporting Russia's claim that the city is encircled. They also noted that Ukrainian officials "directly refute" the claim.

ISW observed evidence that Russian infiltrators, small groups, were operating east and northeast of Dobropillia on 19 and 20 September. The institute did not assess that these infiltrators had consolidated their positions.

Ukrainian forces maintain positions south and northeast of Dobropillia, military observer Kostiantyn Mashovets said on 20 September, according to ISW.

Russian forces have not made major gains in the Dobropillia direction, the chief of staff of an artillery reconnaissance battalion said on 22 September, according to the institute. On the same day, a Russian milblogger described the "alleged Russian encirclement of Dobropillia" as potentially meaning not the direct presence of infantry, but only the establishment of fire control over Ukrainian logistics, including roads west of Dobropillia and toward Sviatohorivka, according to ISW.

ISW noted that Russia's pervasive military culture of lying—what Russian milbloggers themselves call "beautiful reports"—has degraded the Defense Ministry's own ability to understand the battlefield and enabled inflated claims like the Dobropillia encirclement.

Russia uses this disinformation as a "diversion"

In its statement, the Russian Defense Ministry itself described Dobropillia as a "strongly fortified settlement" whose seizure would threaten key Ukrainian supply lines running from Dnipropetrovsk Oblast toward the Fortress Belt—the Sloviansk-Kramatorsk-Druzhkivka urban agglomeration.

Russia has recently renewed its attempts to break through toward Dobropillia.

Third Army Corps Commander Andrii Biletskyi said that Russian forces sought to bypass the fortified cities through Dobropillia and link up with troops advancing from north of Lyman, rather than launch a direct assault. ISW noted on 16 September that the Vivaldi operation disrupted Russia's two-pronged plan. In its 24 September report, ISW said Russia's claims about Dobropillia were partly intended to divert attention from Ukraine's elimination of the Russian salient north of Lyman, which has likely forced Russia's command to rethink its wider encirclement plans.

Ukraine's Vivaldi counteroffensive rolled back a Russian advance north of Lyman in Donetsk Oblast. However, Moscow shifted part of its forces south, Roman Pohorilyi, co-founder of the Ukrainian battlefield mapping project DeepState, told Radio NV. Russian troops are now infiltrating Mykolaivka, a key strongpoint on the approach to the fortress city of Sloviansk, Pohorilyi said.

The halted advance was one arm of Russia's plan to encircle Ukraine's Donetsk fortress belt—the fortified cities of Sloviansk, Kramatorsk, Druzhkivka, and Kostiantynivka. Pohorilyi warned that losing Mykolaivka would create serious problems for Sloviansk's defenders. Russia is still pressing toward Dobropillia on the belt's southwestern flank.

Pohorilyi said Russia formed a "claw" north of Lyman by exploiting Ukrainian brigades short of personnel and pushing small groups into their lines. Ukraine's Third Army Corps stabilized the area, built up forces, and counterattacked. The push "multiplied all [Russia's] previous efforts by zero," he said.

Russian forces had repeatedly tried to capture or bypass Lyman, Pohorilyi said. Russian groups still infiltrate the approaches to the city, although Ukrainian forces have stabilized the situation there.

The corps says Vivaldi's first two phases regained control of 125 square kilometers, including 50 that had been under Russian occupation. It reported liberating Shandryholove and Derylove, securing Drobysheve, and inflicting more than 3,000 Russian personnel losses. Those battlefield figures have not been independently verified.

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Pohorilyi noted that the area around Mykolaivka had, until recently, been under the responsibility of Ukraine's 11th Army Corps and is now under the Third Army Corps.

Ukrainian troops must now find and stop infiltrating Russian groups before they establish control, he said. Personnel shortages on the Lyman axis persist, although he said reinforcements are being distributed more evenly.

Operation Vivaldi and the wider fight for Donetsk's fortress belt

The Third Army Corps first disclosed Operation Vivaldi on 15 September after conducting the counteroffensive north of Lyman under information silence. Commander Andrii Biletskyi said the announced gains were only the first phase; the corps said its attacks had disrupted Russian supply routes.

A 60th Mechanized Brigade captain said Ukrainian units quietly assembled near Derylove and Drobysheve, then struck Russian drone launch sites at planned times so infantry could advance. The corps disclosed a second phase on 20 September.

Farther southwest, Dobropillia faces even heavier pressure, Pohorilyi said. Russia has concentrated large forces there and is pushing with relentless infantry across a wide front, backed by thousands of drones each month—reconnaissance, strike, FPV, and Lancets—with numbers still rising. Russian troops are moving on settlements south of Dobropillia to establish a strongpoint and push deeper into Donetsk Oblast.

The pressure is not new: Biletskyi said Ukrainian troops halted a Russian incursion there last year. After Moscow claimed on 22 September to have encircled the town, the Institute for the Study of War found no evidence to support the claim.

Ukrainian troops pushed into a front-line village Russian forces were sure they could never reach, an officer from the assault force told Army TV. He described a methodical, house-by-house clearing—then a Russian response that, once the village fell, called the footage an AI fake.

Through 2026 Russia has pressed on this stretch of the eastern front, creeping toward the fortress belt, the chain of fortified cities anchoring Donetsk Oblast. Retaking Serednie is one move in a quiet Ukrainian counteroffensive that has clawed back ground on this axis—which is why this village changing hands lands harder than the map suggests.

The terrain Russia trusted

Serednie sits on the Lyman direction in eastern Ukraine, an axis where Russian forces have been pressing toward Ukrainian-held Sloviansk and Kramatorsk. Troops from Ukraine's 66th Separate Mechanized Brigade entered the village during Operation Vivaldi, said the deputy commander of its first mechanized battalion, Kassta, callsign Timokha.

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Sitting on their own gains there, the Russians assumed no counterattack could follow and were certain the terrain itself ruled out any move into the village.

"The enemy, having success in this direction, did not expect that any counterattack or offensive could come in response," Timokha said.

Preparing for the operation took more than a day or two, he added, because the village was full of basements and buildings that each had to be checked. Reconnaissance came first, then fire from drones, heavy bomber drones, and artillery to grind down a garrison he put at at least a platoon, before assault groups moved in with friendly units alongside.

Operation Vivaldi as a whole, run under an information blackout, has cleared 75 km² of enemy infiltration pockets and de-occupied another 10.

Then the Russians called it AI

Small Russian attempts to retake the village broke apart on the approaches, Timokha said. The louder reaction came online: Russians claimed the Ukrainian liberation videos were made with artificial intelligence.

He likened it to Sviatohirsk, where Vladimir Putin announced the town's capture before the commander of Ukraine's Third Army Corps, Brigadier General Andrii Biletskyi, publicly denied it, Timokha said.