A senior commander said troops had consolidated new defensive positions west of Avdiivka, whose capture was the biggest Russian battlefield gain in nine months.

Ukrainian military spokesperson Dmytro Lykhoviy said troops had pulled back from Sieverne and Stepove, a day after Kyiv announced it had abandoned the village of Lastochkyne.

"Our forces withdrew from the small villages of Sievierne and Stepove... Heavy battles for Sievierne went on yesterday in the evening and night," Lykhoviy said, adding that Russia had taken significant losses in that fight.

Ukraine was pulling back to positions level with the rest of the eastern front line, to terrain more suitable for defence, Lykhoviy said.

Sieverne and Stepove had a total population of fewer than 100 people before the invasion.

The ministry said its troops had "occupied more advantageous lines and positions" and struck Ukrainian manpower and equipment near three other settlements.

Reuters could not independently verify the battlefield claims of either side.

Avdiivka had withstood unrelenting Russian barrages since mid-October. The capture of the town, where virtually no buildings remained intact, was the biggest Russian gain since it took the equally devastated town of Bakhmut further northeast last May.

One Ukrainian commander, Oleksandr Tarnavskyi, said on Telegram: "In the Avdiivka sector, the line of defence in the areas of Tonenke, Orlivka and Berdychi has been stabilised."

Russian forces had failed in their attempts to advance in two areas further south, including the hotly contested Ukrainian-held village of Robotyne, the senior general added.

Ukraine's effort to hold Avdiivka, which lies only about 10 km (6 miles) from the key Russian-held city of Donetsk, forced it to defend an awkward salient that protruded into Russian-occupied areas.

U.S. President Joe Biden and top Democrats met with senior Republicans in Congress on Tuesday to press again for the release of some $60 billion in aid for Ukraine.

A White House statement issued after a meeting said Biden "discussed how Ukraine has lost ground on the battlefield in recent weeks and is being forced to ration ammunition and supplies due to congressional inaction."