Ukraine's Third Army Corps confirms "Vivaldi" offensive near Lyman
Ukraine's Third Army Corps publicly confirmed on September 15 that it has been running an offensive operation codenamed "Vivaldi" in the northern part of Donetsk Oblast, east and northeast of Lyman. The corps revealed details of the first phase, which targeted Russian troop infiltration and logistics, and reported Russian losses in personnel, drones and equipment. The announcement broke months of operational secrecy around the fighting.
Key points
- Commander of the Third Army Corps Andriy Biletsky confirmed the operation in a video address on September 15.
- The operation is codenamed "Vivaldi" and had been conducted under full information silence before the announcement.
- The first phase aimed to eliminate Russian infiltration and disrupt Russian logistics in the area east and northeast of Lyman.
- Ukrainian forces cleared Russian footholds in Novoselivka, Oleksandrivka, Yarova and the outskirts of Koroviy Yar, and liberated Serednie.
- The Third Army Corps reported clearing 75 km² and de-occupying an additional 10 km² during the first phase.
- According to the corps, Russian losses in the first phase were about 1,500 personnel, more than 12,000 drones and hundreds of armoured vehicles and artillery systems.
- Independent analysts Clément Molin and the Institute for the Study of War reported that Defense Forces likely cut the Russian salient north of Lyman and liberated about 200 km².
Why it matters
The announcement is the first official Ukrainian confirmation of offensive combat operations in the north of Donetsk Oblast in recent months. The fighting targeted a Russian salient that had threatened the Sloviansk-Kramatorsk agglomeration, the largest remaining populated area in Ukrainian-controlled Donbas. Independent Western OSINT analysts have described the result as one of the most important Ukrainian victories of 2026.
What happened
On September 15, Andriy Biletsky, commander of Ukraine's Third Army Corps, publicly confirmed for the first time that his units have been conducting an offensive operation codenamed "Vivaldi" in the northern part of Donetsk Oblast, east and northeast of the city of Lyman. The operation had been kept under full information silence, with the Ukrainian General Staff declining to comment and the DeepState project not updating its combat map for the area.
Biletsky disclosed the objectives of the first phase: eliminating Russian troop infiltration and disrupting Russian logistics. According to the corps, search-and-strike actions destroyed Russian footholds in the area of Novoselivka, Oleksandrivka, Yarova and the outskirts of Koroviy Yar, and the village of Serednie was liberated and is now fully under the control of the Defense Forces. Drone units of the corps struck Russian supply routes and fuel infrastructure, forcing Russian forces to move fuel and lubricant supplies out of Ukraine into Voronezh Oblast.
The Third Army Corps reported that during the first phase its units cleared 75 km² of territory of Russian infiltration and de-occupied an additional 10 km². Russian losses at this stage were stated as approximately 1,500 personnel, more than 12,000 drones and hundreds of units of armoured vehicles, artillery systems and other equipment. Biletsky said the operation struck a heavy blow to the combat capability of Russia's 20th and 25th Combined Arms Armies.
Biletsky described "Vivaldi" as having four stages — "four seasons," in a reference to Antonio Vivaldi — and said only the first has been completed. He urged continued information silence, promising further updates in official reports. Units involved in the operation included the 60th and 125th Mechanized Brigades, a tactical group of the 3rd Assault Brigade, the 3rd Reconnaissance Battalion, the 25th Anti-Tank Battalion of the corps, the 66th Mechanized Brigade, the 85th Tactical Group of the 8th SSO Regiment, the HUR MOU special unit "Artan" and the 10th Mobile Border Detachment "DOZOR."
How Ukrainian sources describe it
Ukrainian media outlets report the announcement as a direct disclosure by the commander of the Third Army Corps, Andriy Biletsky, centring his video address as the source of the information. Coverage highlights the tactical gains of the first phase — cleared settlements, liberated Serednie, the territory figures and reported Russian losses — and frames the operation as a blow to Russia's 20th and 25th Combined Arms Armies. The outlets note the contrast with the prior information silence: the General Staff had not commented on possible Ukrainian successes in the area and DeepState had not updated its map, making Biletsky's video the first official acknowledgement of the offensive.
Where reporting differs
The Third Army Corps reported clearing 75 km² of Russian infiltration and de-occupying an additional 10 km², a total of roughly 85 km². Clément Molin and the Institute for the Study of War, by contrast, reported that Defense Forces likely cut the Russian salient north of Lyman and liberated about 200 km² — a substantially larger figure than the corps' own numbers.
Background
For months before the September 15 announcement, the operation was kept under full information silence. The Ukrainian General Staff declined to comment on possible Ukrainian successes in the north of Donetsk Oblast, and the DeepState project did not update its frontline map for the area. Independent military analysts had nonetheless been describing Ukrainian advances in the so-called Lyman salient — a zone that posed a threat to the Sloviansk-Kramatorsk agglomeration from the east and northeast — for some time before the official confirmation. French OSINT analyst Clément Molin characterised the operation publicly on September 8, a week before the corps confirmed it.