Commander announces results of Ukraine's Operation "Vivaldi" on Lyman axis

Why it matters

Operation "Vivaldi" is presented as having derailed Russia's stated goal of fully capturing Donetsk Oblast, a key political objective of the Russian military-political leadership. According to Biletsky, the operation inflicted major Russian losses — over 8,000 personnel and the destruction of the 144th Division — and shifted the tactical picture on the Lyman axis by halting frontal assaults on Slovyansk and Kramatorsk. The disclosure that the operation was kept secret for four months, approved by both the former and current commanders-in-chief and supported by Ukrainian and Western OSINT communities, signals a deliberate Ukrainian model of operational concealment applied to a strategically consequential offensive.

What happened

Ukraine's Defense Forces conducted Operation "Vivaldi" on the Lyman axis, a months-long offensive announced publicly on 15 September. The commander of the Third Army Corps and the "Center" force grouping, Andriy Biletsky, presented the operation's results to journalists. He said 277 square kilometers were liberated, with several hundred additional kilometers cleared of infiltration not counted as operational gains. Russian losses totaled more than 8,000 personnel killed and wounded, with 270 fighters taken prisoner, including a battalion chief of staff, 13 reconnaissance platoon commanders and over 20 officers in total. Biletsky reported that 3,800 pieces of Russian equipment were struck during the operation, of which 1,800 were artillery systems, and that the 144th Division of the Russian 20th Army was destroyed and ceased to exist as an organized military force.

Biletsky described the Russian strategic plan as a two-pronged encirclement: one strike through Sviatohirsk around Lyman to envelop the Slovyansk-Kramatorsk agglomeration from the north, and another through Dobropilya toward Barvinkove to complete the capture of Donetsk Oblast. He said the Russian "West" grouping included the 1st Tank Army and the 20th and 25th Combined Arms Armies, and that the plan, conceived in 2025, was scheduled to run through the end of 2026. After the operation, he said, Russia temporarily abandoned the planned encirclement of Donetsk Oblast and frontal assaults on Slovyansk and Kramatorsk, though it intended to resume them later, leaving only the Dobropilya direction active. The Third Corps advanced to the Chornyi Zherebets River, shortening the front line and allowing infantry positions to be thickened.

Biletsky stated that Ukrainian overall losses were seven times smaller than Russian losses, with Russians suffering more killed and Ukrainians more wounded. He added that both former Commander-in-Chief Syrsky and current Commander-in-Chief Drapatyi were aware of the operation and approved the absence of official reports; progress was not entered into the "Delta" situational awareness system over concerns about leaks, and he personally reported to the Commander-in-Chief roughly once every few weeks. He thanked DeepState and ISW for cooperating with the secrecy effort, saying disinformation was even disseminated through them when needed.

How Ukrainian sources describe it

All of the supplied coverage is Ukrainian, and the reporting is centered on Andriy Biletsky as the principal voice presenting the operation's results, loss figures and territorial gains. The outlets highlight the strategic significance of derailing Russia's stated goal of fully capturing Donetsk Oblast and devote significant attention to the operational secrecy that made the offensive possible, including the role of the former and current commanders-in-chief in approving the absence of official reports. Human-interest elements feature prominently: the story of how the operation came to be named "Vivaldi" (after the four-season structure of the original plan and the classical music reportedly played in Third Corps headquarters), and the fate of the two assault fighters "Yurist" and "Lyeshyi" who proposed the name — the latter recently killed after sustaining seven wounds, the former, a Mariupol native, seriously wounded and hospitalized for a long time. Ukrainian cooperation with Western OSINT groups, including DeepState and ISW, is framed positively as part of what enabled the operation's concealment.

Where reporting differs

Sources diverge on Russian claimed territorial gains. According to Biletsky, Russian forces claimed 1,260 square kilometers of Ukrainian gains, but he said this figure includes unrealistic additions such as Sviatohirsk, Oskil and Borova; the Ukrainian map, he said, shows 277 square kilometers of territory actually liberated during the operation (Novynarnia).

The reporting on Russian losses and prisoners also varies in scope. An early third-stage summary on 28 September cited 2,000 Russian personnel lost and more than 250 captured; cumulative totals attributed to the entire operation stand at over 8,000 personnel lost and 270 captured (Interfax-Ukraine and ZN.UA).

Background

Russia's strategic plan on this axis, as described by Biletsky, was a two-pronged encirclement. One strike was to move from a bridgehead on the Chornyi Zherebets River through Sviatohirsk toward Rubtsi, split the Ukrainian grouping on the eastern bank of the Oskil River and envelop the Slovyansk-Kramatorsk agglomeration from the north while bypassing Lyman. A second strike through Dobropilya toward Barvinkove in southern Kharkiv Oblast was meant to complete the encirclement of Donetsk Oblast. The Russian "West" grouping tasked with this plan reportedly included three armies: the 1st Tank Army and the 20th and 25th Combined Arms Armies. The operation is said to have been planned in four seasonal stages, which influenced the choice of the name "Vivaldi" — classical music is reportedly routinely played in Third Corps headquarters — though the original plan was later expanded to more than four stages. The name was proposed by the assault fighters "Yurist" and "Lyeshyi." "Lyeshyi" was recently killed after sustaining seven wounds during assaults before moving to a headquarters role; "Yurist," a Mariupol native, was seriously wounded and has been hospitalized for a long time. By the end of the operation the Third Corps had advanced to the Chornyi Zherebets River, a defensive line Russia would have to cross again to restart its offensive. Russian forces publicly claimed the capture of Sviatohirsk on 1 September, and Biletsky said on 17 September that Ukrainian forces had essentially destroyed the Russian "northern claw." Biletsky stated that Ukrainian overall losses were seven times smaller than Russian losses, with Russians suffering more killed and Ukrainians more wounded. Ukrainska Pravda first wrote about the Russian plan to bypass Donetsk Oblast via Dobropilya and Barvinkove in the summer of 2025.