Ukrainian forces destroyed large Russian division during Operation Vivaldi - ISW
Photo: The enemy suffered massive losses (Getty Images)
Operation Vivaldi and other Ukrainian counteroffensive operations in 2026 have enabled Ukraine to seize the operational initiative along the entire front line and effectively halt the Russian army's advance, according to a report by the Institute for the Study of War (ISW).
According to US analysts, Operation Vivaldi has thwarted Russia's plans to capture the Donetsk region. The Ukrainian counteroffensive disrupted the enemy's attempt to outflank Ukraine's defensive belt from the north and create conditions for encircling it.
The Defense Forces are known to have reached the Zherebets River, allowing them to shorten the front line and establish defenses along more advantageous positions. This enables Ukrainian forces to concentrate more infantry along a shorter section of the front, as well as use drones and artillery more effectively.
Moreover, the report notes that Russian troops will have to cross the Zherebets River again to resume offensive operations in the Lyman direction. Thus, Operation Vivaldi thwarted Russia's attempt to envelop Lyman from the north, particularly via Sviatohirsk, and subsequently link up near Barvinkove in the Kharkiv region with another grouping that was supposed to advance from the southwest via the Dobropillia direction.
In effect, the Ukrainian counteroffensive has derailed Russia's plan for an operational encirclement. Russian forces must now consider a frontal offensive east of Sloviansk and Kramatorsk. This scenario would involve direct attacks on well-prepared Ukrainian defensive positions, significantly complicating the advance and increasing the cost to the enemy.
According to estimates by the Institute for the Study of War, between September 1 and October 16, 2026, Russian forces lost control of approximately 122 square kilometers of territory. At the same time, they have managed to capture around 100 square kilometers since the beginning of 2026.
It is also known that during Operation Vivaldi, Russia's 144th Motor Rifle Division suffered such heavy losses that it effectively ceased to exist as an organized combat formation.
To restore its offensive capabilities in the Lyman direction, Russia will have to rebuild the division's combat readiness. This will place additional strain on the Russian army's recruitment system, which is already facing growing difficulties.
Russian combat losses have been increasing since the summer of 2026. According to the estimates cited, the Russian army has lost more than 40,000 troops killed and wounded over the past several months.
Earlier, we reported that Ukraine had recaptured another 101 square kilometers of territory in Donbas as part of Operation Vivaldi.
