Ukrainian Counteroffensive Thwarts Russian Encirclement Plans

Ukrainian forces halted a Russian effort to encircle the remaining Ukrainian-held area of Donetsk region by defeating a planned deep pincer targeting the so-called fortress belt, according to an assessment by the Institute for the Study of War.

The Russian campaign aimed to link advances from Lyman in the north and Dobropillia in the south-west near Barvinkove in Kharkiv region to complete an encirclement that would facilitate occupation of Donetsk region. Ukraine’s counter-offensive on the Lyman axis, called Operation Vivaldi, dismantled the northern arm of that pincer and recaptured territory along the Ridkodub–Nove–Novomykhailivka and Yarova–Drobysheve–Stavky lines, collapsing the salient threatening Sloviansk from the north-east.

Andrii Biletskyi, commander of Ukraine’s 3rd Army Corps, reported that the first three phases of the operation in mid- to late September liberated 176 square kilometres. President Volodymyr Zelenskyy gave a lower figure of between 125 and 140 square kilometres as of 3 October and stated that Russian losses had risen sharply over the preceding two to three months. ISW suggested that the operation may have been more successful than Kyiv’s official figures reflect.

The defeat of the northern pincer forced Russia to abandon plans to advance on Sloviansk from the north-east and preserved Ukrainian control over the Lyman area and key supply routes. Russian units elsewhere on the front may have been redeployed to reinforce the northern sector. The surviving south-western arm from the Pokrovsk–Dobropillia area now faces more ambitious objectives on its own.

ISW assessed the collapse of the northern pincer as an operational failure for Russia, noting that Russian forces retain limited gains around Kostyantynivka and east of Sloviansk but have struggled to sustain their pace of advance. The institute argued that Russian tactics relying on infantry infiltration, drones and bombardment can produce gradual attrition but cannot deliver the rapid mechanised manoeuvres needed to collapse Ukrainian defences at the required scale.

ISW also challenged pro-government Russian claims that Russian forces occupied an additional 1,301 square kilometres in September. Using geolocated photo and video footage, satellite imagery and visually confirmed data, the institute calculated that Russian assault units were pushed out of at least 80 square kilometres in September, and that Russia’s net retreat in September rose to 175.18 square kilometres when including temporary penetrations that were not held.

President Vladimir Putin told the Valdai Club that Russia now occupies 89% of Donetsk region; ISW put the figure of Russian-occupied territory in the Ukrainian region at no more than 81% and described Putin’s claims of breakthroughs in September as significantly divorced from the verified situation. ISW noted it could not determine whether Putin knowingly cites false figures or has come to believe inaccurate frontline data within the Russian military command.

Liberal News Analysis: What Does This Development Mean?

ISW’s assessment frames the recent fighting as a substantive setback to Moscow’s operational plan to seize the remainder of Donetsk region by encirclement. The dismantling of the northern pincer removed a key element of the campaign aimed at collapsing Ukraine’s fortress belt and protecting approaches to Sloviansk, while preserving Ukrainian control of critical supply lines in the Lyman area.

Russian retention of limited gains around Kostyantynivka and east of Sloviansk, coupled with an ongoing south-western advance from Pokrovsk–Dobropillia, indicates the front remains contested and dynamic. ISW’s analysis highlights that current Russian tactics may yield gradual territorial attrition but lack the mechanised momentum to force a decisive breakthrough across the theatre as Moscow requires.

Discrepancies between Kremlin public claims and ISW’s geolocated and imagery-based estimates underscore persistent challenges within Russian reporting and operational assessment, while the institute warned that further Russian mobilisation or technological adaptation could change dynamics without guaranteeing a breakthrough.

Quick Glance: What You Need to Know

• Ukrainian Operation Vivaldi dismantled the northern arm of Russia’s planned encirclement in Donetsk region.
• Andrii Biletskyi reported liberation of 176 square kilometres in the early phases of the operation.
• Volodymyr Zelenskyy reported 125 to 140 square kilometres liberated as of 3 October and noted rising Russian losses.
• ISW’s analysis suggests Ukrainian gains may exceed Kyiv’s official figures and labels the northern pincer collapse an operational failure for Russia.
• ISW geolocation and imagery analysis found Russian assault units were pushed out of at least 80 square kilometres in September.
• ISW estimated Russian-occupied territory in Donetsk region at no more than 81%, challenging Putin’s 89% claim.