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

The daring campaign Ukraine launched last summer to seize and occupy Russian territory appears to be nearing an end.

Since then, Russian forces – bolstered by thousands of North Korean troops sent by Putin-ally Kim Jong-un – have sought to claw back most of that land. The North Korean troops began arriving in Kursk from late October as part of a mutual defence pact agreed between Putin and Kim.