Ukraine's Third Army Corps announces Operation Vivaldi, recapturing five settlements near Lyman
Ukraine's Third Army Corps confirmed a counteroffensive in northern Donetsk Oblast under the name Operation Vivaldi, recapturing five settlements on the Lyman direction and disrupting Russian attempts to encircle the strategic "fortress belt." The Institute for the Study of War said the operation achieved an operationally important goal of slowing Russia's advance toward Sloviansk, and Kremlin-linked Russian milbloggers acknowledged that Russian forces had lost positions south of Lyman and could not regain ground in the city.
Key points
- Third Army Corps confirmed the operation on September 15 and named it Vivaldi; cleared Novoselivka, Oleksandrivka, Yarova, outskirts of Koroviy Yar, and de-occupied Serednie in the Lyman community.
- ISW report dated September 15 said the operation disrupted Russian attempts to encircle the "fortress belt."
- A Kremlin-linked Russian milblogger agreed Ukrainian successes would delay the Russian advance on Sloviansk and acknowledged vulnerability on the northern flank of Russia's Southern group of forces.
- Another Russian milblogger said Russian forces lost positions south of Lyman and cannot regain control in the city itself.
- Commander Andriy Biletsky estimated enemy losses at about 1,500 soldiers, more than 12,000 drones, and hundreds of armored vehicles, artillery systems and automotive equipment.
- Third Army Corps strikes forced Russia to move fuel and lubricant supplies out of Ukraine to Voronezh Oblast.
- ISW assessed Russian forces continue prioritizing frontal advance from the south and encirclement from the southwest rather than approaching from the east, despite a failed attempt to take Lyman.
Why it matters
Operation Vivaldi represents the first confirmed announcement of a Ukrainian counteroffensive in northern Donetsk Oblast by the Third Army Corps, and ISW assessed it achieved an operationally important goal: disrupting Russian attempts to encircle the "fortress belt" and slowing the push toward Sloviansk. The fact that Russian milbloggers publicly acknowledged lost positions around Lyman and an inability to retake the city suggests the operation produced a measurable Russian reaction rather than a contested tactical skirmish.
What happened
On September 15, the Third Army Corps confirmed a Ukrainian counteroffensive in northern Donetsk Oblast and named it Operation Vivaldi. The corps said it had cleared Novoselivka, Oleksandrivka, Yarova and the outskirts of Koroviy Yar, and de-occupied Serednie in the Lyman community. Corps commander Andriy Biletsky released GoPro footage of the offensive and named the operation. ISW's report for September 15 said the action achieved an operationally important goal of disrupting Russian attempts to encircle Ukraine's "fortress belt." Biletsky estimated Russian losses at this stage of the operation at about 1,500 soldiers, more than 12,000 drones and hundreds of armored vehicles, artillery systems and automotive equipment. He said units of unmanned systems cut Russian logistical routes, and Russian forces moved fuel and lubricant supplies out of Ukraine to Voronezh Oblast. A Kremlin-linked Russian milblogger agreed that Ukrainian successes would delay the Russian advance on Sloviansk and that the northern flank of Russia's Southern group of forces is vulnerable to Ukrainian counterattacks and supply interdiction. Another milblogger said Russian forces had lost positions south of Lyman and could not regain control in the city. ISW assessed that Russian forces continue to prioritize frontal advance on the fortress belt from the south and encirclement from the southwest, rather than approaching from the east, despite the failed push on Lyman.
How Ukrainian sources describe it
Ukrainian outlets centered the Third Army Corps and commander Andriy Biletsky announcing the operation by name, listing the liberated settlements and providing estimated Russian losses, drones and equipment destroyed. They highlighted operational effects on Russian logistics, including the relocation of fuel and lubricant supplies to Russia's Voronezh Oblast, and framed the action as a deliberate disruption of Russian plans to encircle the "fortress belt" and advance on Sloviansk.
How international sources describe it
The available sources are Ukrainian media and the U.S.-based Institute for the Study of War. No separate international editorial framing of the operation is recorded in the material.
Where reporting differs
Russian milbloggers acknowledged publicly that Russian forces lost positions south of Lyman and cannot retake ground in the city, while ISW assessed that the Russian military command may not yet have recognized the loss of the Lyman salient or conceded the tactical initiative in the area, and may be attempting to cut Ukrainian ground lines of communication with the fortress belt from the west.
Background
ISW has been tracking Russian efforts to advance on the "fortress belt" through southern and southwestern approaches rather than from the east. Kremlin-linked Russian milbloggers have criticized Russian commanders for exaggerated reporting that distorts operational planning, and some have alleged that Russian commanders form rapid assault units from untrained personnel to mask the scale of losses and attempt to retake lost positions.