Ukraine reveals covert Operation Vivaldi near Lyman after months of secrecy
Ukraine's 3rd Army Corps publicly revealed on September 15 that it had been conducting Operation Vivaldi, a months-long covert offensive near Lyman in northern Donetsk Oblast, since May. The operation, kept hidden from Russia through strict information silence, halted a Russian push to encircle the Donbas 'belt of fortress cities' and inflicted heavy losses on Russian forces. Russian troops have since redirected south of Lyman and are pressing on the village of Mykolaivka.
Key points
- Operation Vivaldi was a Ukrainian offensive near Lyman in northern Donetsk Oblast, carried out by the 3rd Army Corps under commander Andrii Biletsky.
- The operation ran covertly since May 2025 under OPSEC conditions; the 3rd Corps asked Western OSINT analysts to stop publishing geolocation data from the area.
- Biletsky publicly confirmed the operation on September 15, 2025; on September 20 he confirmed the de-occupation of Shandryholove, Derylove, and full control over Drobysheve.
- As of September 15, official figures reported 75 sq km cleared and 10 sq km de-occupied, with enemy losses of about 1,500 personnel and over 12,000 drones.
- By September 20, the 3rd Corps said enemy losses had risen to 3,000 personnel and that an additional 40 sq km had been liberated.
- The 3rd Corps said Russia's elite Rubikon drone unit was withdrawn from the Lyman-Borova direction due to heavy losses.
- After being stopped north of Lyman, Russian forces redirected troops south and are pressing on Mykolaivka, described by analysts as an outpost before Sloviansk.
Why it matters
Operation Vivaldi demonstrates that Ukraine was able to conduct a months-long offensive on a key axis of the Donbas front without Russian military or political leadership detecting it, even as Russia publicly claimed advances around Lyman and Sviatohirsk. The operation halted Russian efforts to encircle Ukraine's 'belt of fortress cities' in the Donbas and inflicted heavy losses on Russia's 20th and 25th armies and the elite Rubikon drone unit. However, the subsequent Russian pivot south toward Mykolaivka shows that the pressure on this section of the front has shifted rather than dissipated.
What happened
Ukraine's 3rd Army Corps, commanded by Andrii Biletsky, publicly revealed on September 15, 2025 that it had been running Operation Vivaldi, a covert offensive near Lyman in northern Donetsk Oblast, since May 2025. The operation was conducted under strict OPSEC: the corps asked Western OSINT analysts to stop publishing geolocation updates from the area, and Russian analysts — who typically rely on Western open-source geolocators — did not detect the frontline changes before early September. French OSINT analyst Clément Molin first noticed changes in satellite imagery in June. As of September 15, Ukraine's Defense Forces reported 75 sq km cleared and 10 sq km de-occupied, with Russian losses of approximately 1,500 personnel, over 12,000 drones, and hundreds of armoured vehicles, artillery systems and automotive equipment. On September 18, the 3rd Corps said Russia's elite Rubikon drone unit had been withdrawn from the Lyman-Borova direction due to heavy losses. On September 20, Biletsky confirmed the de-occupation of Shandryholove and Derylove and full control over Drobysheve, adding 40 sq km of liberated territory, and the 3rd Corps put Russian personnel losses at 3,000. Biletsky said Ukrainian forces had essentially defeated the Russian 'northern claw' and halted the Russian offensive, while ISW wrote that Operation Vivaldi disrupted Russian attempts to encircle Ukraine's 'belt of fortress cities' in the Donbas. After being stopped north of Lyman, Russian forces redirected some troops south of the city and are now pressing on the village of Mykolaivka.
Where reporting differs
Sources report different totals for liberated versus fully de-occupied territory. Official figures as of September 15 put cleared territory at 75 sq km and de-occupied territory at 10 sq km. The 3rd Corps press service later added 40 sq km from the liberation of Shandryholove, Derylove and Drobysheve. Texty.org.ua cites a higher overall figure of 125 sq km liberated, of which 50 sq km fully de-occupied.
Background
Ukraine's 3rd Army Corps took over the area north of Lyman after previous brigades there began failing in defense, allowing Russian forces to form a 'claw' north of the city. DeepState co-founder Roman Pohorily described personnel shortages as an ongoing issue for Ukrainian forces in the Lyman direction, though he said the situation began improving after a change in Armed Forces command. Pohorily linked recent changes in personnel distribution — away from concentrating on assault regiments toward fairer distribution between brigades — to discussions involving the president and deputy head of the Office of the President Pavlo Palisa.