Moscow says it has thwarted a Ukrainian attempt to penetrate its southwestern border as it pounded Kiev with missiles, killing three including a child.
The Ukrainian capital faced nearly nightly air raids throughout last month.
As Kiev deployed its air defences against a fresh volley of Russian missiles, Moscow said it pushed back an attempt by Ukrainian troops to invade its southwestern Belgorod region at about 3:00 AM (0000 GMT).
“Overall, the attack involved up to 70 militants, five tanks, four armoured vehicles, seven pickup trucks and a Kamaz truck,” the Russian defence ministry said in the evening, reporting at least three attempted crossings.
It said it used the air force and artillery to repel the attacks, killing more than 50 Ukrainian fighters.
Two long-range drones attacked fuel and energy infrastructure in Russia’s western Smolensk region overnight, but no injuries or fires were reported, the region’s acting governor said.
He said the attacks hit the towns of Divasy and Peresna near the region’s capital Smolensk, some 270 kilometres (168 miles) from the Ukrainian border, but did not say who was responsible.
The incident comes a day after the governor of Russia’s Belgorod region said Ukraine’s armed forces shelled the border town of Shebekino, setting alight a dormitory and damaging an administrative building. Ukraine, meanwhile, denies it is responsible for attacks within Russian territory.