President Vladimir Putin said on Thursday that Russia had trapped the remaining Ukrainian soldiers in its western Kursk region, where they have clung on for more than seven months in one of the key battles of the war.

Russian forces have begun an assault on the town of Sudzha, the main population center in the Kursk region that was captured by Ukraine last year, a top Russian commander said on Tuesday. The advance puts Moscow on the verge of ending the first invasion of Russian territory since World War II.

Russia said on Thursday there was no doubt that its troops would soon complete the task of clearing out Ukrainian forces from Russia's Kursk region where they have held a pocket of territory for more than seven months.