Russia has withdrawn its troops from the strategic Ukrainian town of Lyman, in a move seen as a significant setback for its campaign in the east.
The retreat came amid fears thousands of soldiers would be encircled in the town, Russia's defence ministry said.
Recapturing Lyman is of strategic significance for Ukraine.
The town had been used as a logistics hub by Russia, and could give Ukrainian troops access to more territory in the Donetsk and Luhansk regions.
Video footage shared online showed Ukrainian soldiers waving their national flag on the outskirts of the town.
The battlefield setback prompted the Chechen leader and hardline Moscow ally, Ramzan Kadyrov, to comment that Russia should consider using low-yield nuclear weapons in the face of such defeats.