Ukraine says its forces have cleared Russian infiltrators and retaken territory in northern Donetsk, while the broader scope of “Operation Vivaldi” remains undisclosed.
By Benjamin Murdoch
15/09/2026
Euromaidan Press
Ukraine’s Third Army Corps has revealed details of an offensive operation in northern Donetsk Oblast, saying its forces cleared Russian infiltrators from several settlements and liberated the village of Serednie.
Russia has made seizing the entirety of Donetsk Oblast both a battlefield and diplomatic priority of its invasion of Ukraine, repeatedly trying to break through heavily fortified Ukrainian defensive lines while demanding that Kyiv withdraw from the remaining Ukrainian-held territory in negotiations. Despite years of fighting and sustained Russian assaults, Moscow has failed to capture the entire oblast, and Ukraine is now conducting an offensive of its own.
The operation, dubbed “Vivaldi,” was conducted under a period of information silence and involved Ukrainian drone, reconnaissance, special operations, infantry, and other units working under a unified tactical command. The corps said the first phase cleared 75 square kilometers of Russian infiltrators and liberated another 10 square kilometers of territory.
The announcement was made by Third Army Corps commander Brigadier General Andrii Biletskyi on 15 September.
Ukraine targets Russian infiltration
According to the corps, the operation focused initially on Russian troops that had infiltrated Ukrainian positions and settlements in the area.
Ukrainian forces cleared Novoselivka, Oleksandrivka, Yarova, the outskirts of Korovyi Yar, and liberated Serednie, the corps said. It described the total area cleared or retaken as 85 square kilometers.
The operation brought together units from the 60th and 125th Mechanized Brigades, the Third Assault Brigade, the KRAKEN special unit, and other formations of the Third Army Corps, alongside attached units from the 66th Mechanized Brigade, Ukraine’s Special Operations Forces, the military intelligence unit Artan, and the State Border Guard Service.
The corps said the operation was coordinated by a joint headquarters that brought special operations and reconnaissance units under a single tactical plan specifically to counter Russian infiltrators, whom it referred to as “flagovtyky.”
Russian logistics pushed back across the border
The Ukrainian operation also targeted Russian logistics supporting the front.
The corps said its drone units cut Russian supply routes and struck fuel infrastructure and storage facilities that had been supporting Russian forces.
According to the Ukrainian military, Russian forces subsequently moved the supply of fuel and lubricants out of Ukraine and into Russia’s Voronezh Oblast after a pipeline and fuel depots were destroyed.
The corps claimed Russian forces lost around 1,500 personnel during this phase of the operation, as well as more than 12,000 drones and hundreds of armored vehicles, artillery systems, and other vehicles.
‘This is only the first season’
Biletskyi said the operation’s ultimate objective has been the subject of speculation in open sources, with some reports suggesting Ukrainian forces could be seeking to reach the Chornyi Zherebets River.
He declined to confirm that objective, instead emphasizing the name of the operation.
“Our operation is called Vivaldi. And Vivaldi, as is known, has four seasons. And this is only the first one,” Biletskyi said.
The remarks suggest Ukraine does not consider the actions revealed on 15 September to be a standalone tactical operation, although the corps did not disclose what its next phase will involve.
The Third Army Corps said further details would be released in subsequent official statements.
Donetsk Oblast is central to Russia’s territorial demands in Ukraine. Moscow claims the entire oblast as Russian territory despite not controlling all of it, and has demanded that Ukraine withdraw from the remaining Ukrainian-held territory in Donetsk as part of peace talks.
The Donbas region – consisting of Donetsk and neighboring Luhansk oblasts – has been a battleground since Russia’s 2014 invasion, and capturing the remaining Ukrainian-held territory has remained the Kremlin’s core objective throughout the full-scale invasion since 2022.