Ukraine’s counter-offensive around Lyman appears to have disrupted a wider Russian plan to encircle Ukrainian-held territory in Donetsk, according to an assessment by the Institute for the Study of War (ISW). The analysis says the operation, referred to as “Operation Vivaldi” by Ukrainian military officials, dismantled the northern arm of a Russian pincer movement and forced Russian units onto the defensive.
The assessment is based primarily on open-source information, including geolocated images, video footage, satellite imagery and other visually confirmed data. ISW cautioned that the battlefield remains fluid and that Russian forces could adapt, but concluded that Ukraine has so far halted a major element of Moscow’s offensive plan in the Donbas.
How Ukraine’s Lyman operation affected Russia’s plan
According to ISW, Russia’s campaign was built around a two-sided advance aimed at the Ukrainian-held “fortress belt” in Donetsk. This defensive and logistical network includes positions protecting key cities and routes in the region.
The northern arm advanced from the Lyman area, while the southern-western arm moved from the Pokrovsk–Dobropillia direction. The apparent objective was to link the two advances near Barvinkove, in Kharkiv region, potentially cutting off Ukrainian forces and opening a route towards the remaining Ukrainian-controlled parts of Donetsk.
Ukraine’s counter-offensive focused on the northern sector. ISW said Ukrainian forces advanced along several lines north and south of Lyman, including the Ridkodub–Nove–Novomykhailivka and Yarova–Drobysheve–Stavky directions. These advances reduced the Russian salient that had threatened Sloviansk from the north-east.
The result was more significant than the loss of individual positions. By retaining control around Lyman, Ukraine also preserved important supply routes and prevented Russia from using the area as a launch point for a broader move against the fortress belt.
Territorial gains reported by Ukraine
Andrii Biletskyi, commander of Ukraine’s 3rd Army Corps, said the first three phases of the operation in mid-to-late September resulted in the liberation of 176 square kilometres. President Volodymyr Zelenskyy gave a lower estimate of between 125 and 140 square kilometres as of 3 October.
ISW suggested that the operation may have achieved more than Kyiv’s publicly stated figures indicate. The institute’s assessment did not treat the reported figures as a definitive measure of the entire battlefield, but used available visual evidence to evaluate changes in control.
Russia’s remaining advance faces greater pressure
The collapse of the northern pincer means that Russia’s advance from the Pokrovsk–Dobropillia area is now operating without the support of the original two-direction encirclement plan. ISW said this surviving axis faces more demanding objectives on its own.
Russian forces continue to hold limited gains near Kostyantynivka and east of Sloviansk. However, the assessment said the pace of advance has been difficult to sustain. Russian units have increasingly relied on infantry infiltration, drones and artillery or other bombardment, tactics that can impose gradual pressure but may not produce the rapid mechanised manoeuvres needed to break Ukraine’s defensive network.
ISW described the failure of the northern pincer as an operational setback for Russia. The issue is not only the ground lost around Lyman, but also the loss of positions intended to threaten the northern approaches to Ukrainian-held Donetsk.
- Russia’s northern route towards the fortress belt has been disrupted.
- Ukraine has retained control of the Lyman area and associated supply routes.
- The Russian advance from the south-west must now pursue broader objectives without a matching northern thrust.
- The battlefield remains changeable, with potential Russian adaptations still possible.
ISW disputes Russian claims about September gains
The institute also challenged claims circulated by Russian state-aligned media that Russian forces captured 1,301 square kilometres of Ukrainian territory during September. ISW said its review of geolocated evidence instead indicated that Russian assault units had been pushed out of at least 80 square kilometres during the month.
When temporary penetrations that were not held are included, the institute calculated a net Russian retreat of 175.18 square kilometres in September. Such assessments can change as new imagery and battlefield evidence become available, but they directly contradict the larger territorial gains claimed in Russian reporting.
ISW also disputed a figure attributed to Russian President Vladimir Putin, who said Russia occupied 89% of Donetsk region. The institute estimated that Russian forces controlled no more than 81% of the region.
The competing figures illustrate the difficulty of assessing the war through official statements alone. Front lines can shift rapidly, temporary incursions may be mistaken for sustained control, and access to independent verification remains limited. ISW’s methodology relies on publicly available evidence rather than direct access to military command information.
What happens next in the war in Ukraine?
ISW said Russia could attempt to adjust its tactics, reinforce the northern sector or use additional mobilisation and technological changes to restore momentum. The assessment warned, however, that these steps would not automatically produce a breakthrough.
For Ukraine, holding the Lyman area will remain important because it protects routes into the wider defensive system around Sloviansk and the northern Donetsk front. The immediate significance of the counter-offensive is therefore both territorial and operational: it has limited Russia’s ability to execute the encirclement plan described in the assessment.
The development is part of the wider European security crisis created by Russia’s full-scale invasion of Ukraine. It also remains central to EU foreign policy, European defence discussions and international debates over military support for Kyiv. The ISW assessment is not a government statement or a formal battlefield communiqué, and future changes could alter its conclusions.
Key takeaway
The latest analysis indicates that Ukraine’s Lyman counter-offensive has disrupted a central Russian objective in Donetsk by collapsing the northern arm of a planned pincer movement. Russia still holds territory and retains offensive capability, but its original route towards encircling the Ukrainian-held fortress belt has been weakened, leaving the next phase of the campaign dependent on whether Moscow can generate a new operational approach.
