The governor of Russia's border area of Belgorod, on Wednesday, declared a region-wide state of emergency, citing continued attacks by Ukrainian forces.
"The situation in the Belgorod region continues to be extremely difficult and tense," Vyacheslav Gladkov said in a video posted on the Telegram messaging app.
"Therefore, we are making a decision, starting today, to declare a regional emergency situation throughout the Belgorod region...with a subsequent appeal to the government to declare a federal emergency situation," Gladkov said.
Daily shelling by the Ukrainian armed forces had destroyed houses, killing and wounding civilians, he added.
Ukrainian soldiers crossed the Russian border, about 530 km south-west of Moscow, a week ago, in a surprise attack that President Vladimir Putin said was aimed at improving Kyiv's negotiating position ahead of possible talks and slowing the advance of Russian forces along the rest of the front.
A few days ago, Russia declared a "federal-level" emergency in the Kursk region following the large-scale incursion by Kyiv.
Russian war bloggers reported intense battles across the Kursk front as Ukrainian forces tried to expand their control near Lgov, Bolshoy Soldatskoye, and Korenevo - though they said Russia was bringing in both soldiers and heavy weaponry and repelled some of the Ukrainian attacks.
US President Biden, in his first substantive comments, said Washington is in constant contact with Kyiv about the operation, although the White House said earlier it was not engaged in any aspect of planning or preparation.
"It's creating a real dilemma for Putin," Biden said.
Russia invaded Ukraine in February 2022 and now controls 18 per cent of Ukrainian territory. Ukraine had been losing territory to Russian forces despite hundreds of billions of dollars in US and European support aimed at stopping and even reversing the Russian advance.

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