Ukraine's 3rd Army Corps announces 'Vivaldi' operation near Lyman, says 75 km² cleared

Biletsky, who commands the 3rd Army Corps, disclosed the operation on Tuesday, September 15, saying its first task was to dismantle Russia's so-called infiltration tactics, which he said reach tens of kilometers into Ukrainian battle formations.

The monitoring project DeepState marked the village of Serednie in Kramatorsk district as liberated by Ukrainian forces. Analysts also reported that Russian units have been pushed back from positions near Shandryholove; both settlements are in the Lyman community. According to DeepState, the total area of returned territory around Serednie is 12.5 km², and it has been under Ukrainian control since May.

"One of the advantages the Russians consider theirs is the so-called tactic of infiltration, which in places reaches tens of kilometers deep into our battle formations, so one of the first tasks of the Third Army Corps was to destroy it," Biletsky said.

According to him, the corps' strikes severed the enemy's logistics routes. Russian troops moved fuel and lubricant supplies to the Voronezh region, rolled up a pipeline and relocated warehouses. Biletsky estimated the losses of Russia's 20th and 25th armies at roughly 1,500 soldiers, more than 12,000 drones and hundreds of armored vehicles, artillery pieces and motor vehicles. The figures cannot be independently verified.

Biletsky urged against rushing to conclusions about the operation's ultimate goal. He called rumors that Ukrainian troops aim to reach the Chornyi Zherebets River premature. "Our operation is called 'Vivaldi.' And Vivaldi, as is well known, has four seasons. And this is only the first of them," the commander said.

Independent OSINT analysts had previously written about the scale of the operation. French researcher Clément Molin said the counteroffensive north of Lyman began in late May, but information about it was deliberately withheld for almost four months. In his assessment, Ukrainian forces during that time cut off the Russian salient north of the city and liberated more than 200 km², pushing the enemy back beyond the Zherebets River. Molin called the operation one of Ukraine's most significant victories of 2026 and noted that its success could complicate further Russian advances on Lyman, Izyum and Sloviansk.

The Institute for the Study of War (ISW) offered similar assessments. Its experts wrote that Russian military bloggers acknowledge Ukrainian counterattacks in the Lyman direction and criticize the command for concealing territorial losses with fictitious reports of success.

Russia's Defense Ministry traditionally does not comment on troop retreats. In early September, Vladimir Putin claimed Russian troops had captured Sviatohirsk; Biletsky responded by recording a video walking through the city, which on the map lies in the relative rear of Ukrainian forces.

Sources differ: the 75 km² of cleared territory and 10 km² de-occupied claimed by the 3rd Corps are Ukrainian figures cited by the corps commander. DeepState estimates the area of returned land around Serednie far more modestly, at 12.5 km². Clément Molin and ISW speak of more than 200 km² liberated, citing open-source analysis. The Russian losses of 1,500 soldiers and 12,000 drones are cited only by Biletsky, with no independent confirmation of those figures.