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.

Russia's attempt to encircle the fortified cities of Donetsk Oblast has lost its northern pincer, the commander of Ukraine's Third Army Corps, Brigadier General Andrii Biletskyi, said in a television interview reported by Ukrinform. He described where the two Russian pincers were meant to meet, far behind the front line, and what Moscow must do now that one of them is gone. He also named what the Ukrainian operation there is meant to achieve, after declining to do so when he revealed it two days earlier.

Two pincers that were to meet in another oblast

Biletskyi set out the Russian design "to envelop the so-called fortress cities from the north and from the south"—the four cities, Sloviansk, Kramatorsk, Druzhkivka, and Kostiantynivka, that have been the backbone of Ukraine's defense in the oblast since 2022..

"From the south it was an envelopment through Dobropillia, and from the north through this salient, which is now being cut off, it went to the city of Sviatohirsk and further, to the settlement of Barvinkove, where these two claws of the Russian army, the Dobropillia one from the south and the Sviatohirsk one from the north, were supposed to close," the commander said.

Barvinkove sits in Kharkiv Oblast, west of the fortified belt. The distance from there to the current front line shows how far behind Ukrainian lines the ring was meant to close.

Neither pincer got near it. Ukrainian forces stopped the Russian infiltration near Dobropillia last year, Biletskyi said, and the situation there remains difficult but under control. Russian assault groups have kept pushing toward the town in recent weeks, though Ukrainian troops have mined or destroyed the main approaches.

On the northern pincer he was blunt: 

"The northern claw has effectively been routed and destroyed," he said.

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Now the cities have to be stormed

Holding that result now depends on Russian supply, Biletskyi said. The critical task is "paralyzing logistics, paralyzing the rear areas, not letting the Russians restore this offensive."

He then set out what the failure costs Moscow.

"Then they will have to storm the Sloviansk-Kramatorsk and the Druzhkivka-Kostiantynivka agglomerations head-on," he said. "And storming these cities head-on is a far more painful and costly business for them than trying to envelop them and effectively take them without a fight."

Russia has taken none of them: it has been fighting for Kostiantynivka since October 2025 and has not reached the other three. Ukraine reinforced the sector last month, placing two newly formed groupings under Azov commanders. One of them has since warned that Russia may mobilize up to 600,000 troops for its next offensive.

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What Vivaldi is actually for

Two days after the operation was made public without a stated objective, Biletskyi gave one, and it is defensive.

"Our main strategic task for the Armed Forces of Ukraine is defense on the Donetsk and Luhansk axes, the defense of Donetsk and Luhansk oblasts," he said.

Ukrainian forces are not trying to take as much ground as they can, he added. 

"We are not fighting there just for tens or hundreds, and at one time thousands, of kilometers. We are fighting first of all for favorable defensive lines."

Vivaldi is meant to put the troops on exactly those lines. That sets a different yardstick than captured settlements: the operation will be judged on the ground Ukraine ends up holding, not on how much of it there is.