An official in the Kursk border region of Russia on Monday urged more residents to evacuate due to the "very tense situation" in the area, where Russian forces are still scrambling to respond to a surprise Ukrainian attack after almost a week of fierce fighting.
Russia's emergency authorities say more than 76,000 people have fled their homes in areas of Kursk, where Ukrainian troops and armor poured across the border on Aug. 6, reportedly driving as deep as 30 kilometers (19 miles) into Russia and sowing alarm.
Ukrainian forces swiftly rolled into the town of Sudzha about 10 kilometers (6 miles) over the border after launching the attack. They reportedly still hold the western part of the town, which is the site of an important natural gas transit station.
The Ukrainian operation is taking place under tight secrecy, and its goals - especially whether Kyiv's forces aim to hold territory or are staging a raid - remain unclear. The stunning maneuver that caught the Kremlin's forces unawares counters Russia's unrelenting effort in recent months to punch through Ukrainian defenses at selected points along the front line in eastern Ukraine.
Russia has seen previous incursions into its territory during the nearly 2 1/2-year war, but the foray into the Kursk region marked the largest attack on its soil since World War II, embarrassing President Vladimir Putin and constituting a milestone in the hostilities.