At the height of the campaign, Ukrainian forces controlled some 500 square miles of Russian territory. Now they hold just a small sliver of land along the border.

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.

A rapid Russian advance in recent days left remaining Ukrainian forces increasingly isolated under withering assaults, and they had pulled out from all but a sliver of Kursk provi