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.

On Feb. 25, an elite Russian drone group—the Rubicon Center of Advanced Unmanned Systems—launched a devastating wave of attacks on the main supply line supporting the Ukrainian garrison in Sudzha, the center of the Ukrainian-held salient in western Russia’s Kursk Oblast.