Russia said on Monday its forces had made important gains in eastern Ukraine while continuing to fend off a new Ukrainian offensive inside the Kursk region of western Russia, where a second day of fierce fighting was under way.

Ukraine launched a new offensive in Russia's Kursk region Sunday, Moscow and Kyiv said. Ukrainian forces had captured about 500 square miles of the western Russian province in a surprise incursion in August, but Russian and North Korean troops are believed to have retaken 40-50% of that area.