Russian forces were on Monday advancing in southern Ukraine and had pierced part of the Ukrainian lines less than 31 miles southeast of the city of Zaporizhzhia, according to Russian officials and pro-Russian military bloggers.

Reuters could not independently verify the assertions and there was no immediate comment from Ukraine.

Russia's Defense Ministry said in a statement that its forces had taken the village of Stepove in the Zaporizhzhia region, pushing through Ukrainian lines.

Yuri Podolyaka, one of the most influential pro-Russian military bloggers, said Russian forces had also smashed their way into the nearby village of Maly Shcherbaky.

"Our units have broken through the first line of defense in the Zaporizhzhia direction," Podolyaka said.

Russia on Sunday tried to drive the last Ukrainian soldiers from western Russia, after a seven-month incursion by Ukraine that aimed to distract Moscow's forces, gain a bargaining chip and rile President Vladimir Putin.