Ukraine's 3rd Army Corps confirms 'Vivaldi' counteroffensive in northern Donetsk
Ukraine's 3rd Army Corps publicly confirmed and released GoPro footage of its 'Vivaldi' offensive in northern Donetsk Oblast, saying it restored control over five settlements on the Lyman direction. The Institute for the Study of War assesses the operation disrupted Russian plans to encircle the Sloviansk–Kramatorsk 'fortress belt', a goal even Kremlin-linked Russian bloggers partly acknowledge.
Key points
- 3rd Army Corps on September 15 confirmed a Ukrainian counteroffensive in northern Donetsk Oblast, clearing Novoselivka, Oleksandrivka, Yarova, outskirts of Koroviy Yar, and de-occupying Serednie in the Lyman community.
- Corps commander Andriy Biletsky named the operation 'Vivaldi' and released GoPro footage of the advance.
- 3rd Army Corps reported clearing 75 square kilometers and de-occupying a further 10 square kilometers on the northern Donetsk axis.
- ISW assessed on September 15 that Vivaldi achieved an operationally significant goal by disrupting Russian attempts to encircle the Sloviansk–Kramatorsk 'fortress belt'.
- Corps said it neutralized the elite Russian unmanned-systems unit 'Rubicon' on the Lyman–Borivka direction, forcing its withdrawal.
- Biletsky cited enemy losses of roughly 1,500 soldiers, more than 12,000 drones, and hundreds of armored vehicles, artillery systems and vehicles.
- Unmanned-systems units cut Russian logistics; strikes pushed Russian fuel and lubricant stocks out of Ukraine to Voronezh Oblast, according to the corps.
Why it matters
Vivaldi is the first official Ukrainian confirmation of a counteroffensive in northern Donetsk Oblast, and the ISW judges it has already disrupted Russian plans to encircle the Sloviansk–Kramatorsk 'fortress belt' — a strategic anchor of Ukraine's defensive line in the region. Even Kremlin-linked Russian bloggers concede the gains have delayed the Russian push on Sloviansk and exposed the northern flank of Russia's Southern group of forces. The reported neutralization of the elite Russian 'Rubicon' unmanned-systems unit underlines the growing role of drones in shaping the front. Internal Russian commentary cited in the ISW report points to command-level problems — exaggerated advance claims and the hasty formation of assault units from untrained personnel to mask losses — that may compound the operational pressure on Moscow.
What happened
On September 15, 2026, Ukraine's 3rd Army Corps publicly confirmed a counteroffensive in northern Donetsk Oblast and released GoPro footage of the fighting. Corps commander Andriy Biletsky named the operation 'Vivaldi' and showed footage of the liberated territories. The corps said Ukrainian forces had cleared Novoselivka, Oleksandrivka, Yarova and the outskirts of Koroviy Yar, and had de-occupied Serednie in the Lyman community — five settlements in all — and reported clearing 75 square kilometers and de-occupying a further 10 square kilometers. Biletsky cited enemy losses of approximately 1,500 soldiers, more than 12,000 drones and hundreds of armored vehicles, artillery systems and motor vehicles; these figures are estimates from one side and have not been independently verified. The corps said unmanned-systems units cut Russian logistics and that strikes forced Russia to move fuel and lubricant supplies out of Ukraine to Voronezh Oblast. Combat footage released by the corps showed MLRS and heavy bomber strikes in the Lyman direction destroying Russian troop concentrations, a crossing, an ammunition depot, a UAV crew, a gun and an enemy MLRS. The corps also said it had inflicted losses on Russia's elite 'Rubicon' unmanned-systems unit, described as a center for advanced strike, FPV and reconnaissance drones, forcing its command to pull it from the Lyman–Borivka direction. ISW, in a report dated September 15, assessed that Vivaldi achieved an operationally significant goal by disrupting Russian attempts to encircle the 'fortress belt' of Sloviansk and Kramatorsk, and that Ukrainian successes north of Lyman had made a Russian encirclement of the fortress cities from the north and south 'unrealistic'. Kremlin-linked Russian bloggers partly echoed that reading, acknowledging that Ukrainian gains would delay the Russian advance on Sloviansk and that the northern flank of Russia's Southern group of forces is vulnerable to Ukrainian counterattacks.
How Ukrainian sources describe it
Ukrainian sources center the official 3rd Army Corps narrative: a confirmed counteroffensive in northern Donetsk, cleared settlements on the Lyman direction, commander Andriy Biletsky publicly naming the operation 'Vivaldi', and a tally of enemy losses of roughly 1,500 soldiers, more than 12,000 drones and hundreds of armored vehicles, artillery systems and motor vehicles. They emphasize the strategic motive — preventing the encirclement of Sloviansk and Kramatorsk — and credit tactical factors such as information silence and exceeding planned objectives for the operation's success. They also highlight the damage to the elite Russian 'Rubicon' unmanned-systems unit and its reported withdrawal from the Lyman–Borivka direction as a concrete result of the offensive.
Where reporting differs
Russian milbloggers claim Russian forces lost positions south of Lyman and cannot regain positions in the city itself, while ISW assesses that the Russian command has likely not yet realized the loss of the Lyman salient and the tactical initiative in the area, and may still be trying to cut Ukrainian ground lines of communication with the 'fortress belt' from the west. Russian war correspondents also blame field commanders and a culture of 'beautiful reports' for aiding Ukrainian successes, while another Russian blogger claims the higher Russian command 'understands the situation on the ground' — leaving open whether the problem is local command behavior or a systemic issue acknowledged at the top.
Background
The 'fortress belt' refers to the Ukrainian defensive line anchored on Sloviansk and Kramatorsk in Donetsk Oblast. Russian forces had been attempting to encircle this belt from the south and southwest; the Ukrainian advance north of Lyman is assessed by ISW to have made that encirclement plan 'unrealistic'. Russian forces reportedly relocated fuel and lubricant supplies to Voronezh Oblast in response to Ukrainian strikes on logistics routes.