Ukrainian President Volodymyr Zelenskiy said on Sunday that fighting was going on in a string of villages in the northeastern Kharkiv region as Russian forces tried to press their drive across the border.
Zelenskiy, speaking in his nightly video address, also noted fierce battles in various parts of Donetsk region to the southeast.
Zelenskiy said "defensive battles" were taking place along large sections of the border in Kharkiv, where Russian forces launched a major armoured push on Friday.
"There are villages that have in fact been turned from a 'grey zone' into a zone of hostilities," the president said. "The occupier is trying to gain a foothold in some of them, while others are being used to advance further."
He said fighting was "no less acute" in some areas of Donetsk region, the focal point of Russia's slow drive to occupy all of eastern Ukraine.
Thirty armed clashes had occurred in the past 24 hours, he said, in the Pokrovsk sector, northwest of the Russian-held town of Avdiivka, and there was also fighting in the sectors of Lyman, Kupiansk, Kramatorsk and other areas
