At least three people were killed and dozens of homes damaged by blasts in the Russian city of Belgorod near the Ukraine border, the regional governor said on Sunday, while Ukrainian forces struck a Russian military base in occupied southern Ukraine.
Belgorod Governor Vyacheslav Gladkov reported several explosions in the city of nearly 400,000, some 40 km (25 miles) north of the border with Ukraine.
At least 11 apartment buildings and 39 houses were damaged, including five that were destroyed, Gladkov said on the Telegram messaging app.
"The sound was so strong that I jumped up, I woke up, got very scared and started screaming," a resident of the city told Reuters, adding the blasts occurred around 3 a.m. (0000 GMT)
"The missile hit residential buildings about 20 metres from my house," the resident said. "All the windows in our house were shattered, the doors came out of alignment."
Senior Russian lawmaker Andrei Klishas accused Ukraine of shelling Belgorod and called for a stern response.
"The death of civilians and the destruction of civilian infrastructure in Belgorod are a direct act of aggression on the part of Ukraine and require the most severe - including a military - response," Klishas wrote on Telegram.
Moscow has accused Kyiv of numerous attacks on Belgorod and other regions bordering Ukraine since Russia's Feb. 24 invasion. Ukraine has not claimed responsibility but has described the incidents as payback and "karma" for Russia's actions.
There was no immediate comment from Ukraine and Reuters could not independently verify the Russian accounts.
In the Russian-occupied southern Ukraine city of Melitopol, Ukrainian forces hit a military base with more than 30 strikes on Sunday, the city's exiled mayor said in a video address on Telegram.
The base had been "taken out of action", Ivan Fedorov said.
A Moscow-installed official said several private residential houses near the airfield were damaged.
"Shells fell on the territory of the airfield. There were no casualties," Evgeny Balitsky, head of the Russia-installed council in the southern Zaporizhzhia region, wrote on Telegram.
The General Staff of Ukraine's Armed Forces said its air force had flown some 15 sorties "in virtually all directions of hostilities".
“About 20 units of enemy equipment and two field ammunition depots were destroyed.”
Reuters could not immediately verify the accounts.
Thousands of civilians have been killed and cities levelled since Russia invaded in what Ukraine its Western allies say is an unprovoked war of aggression. Russia denies targeting civilians in what President Vladimir Putin calls a "special military operation" to demilitarise and "denazify" its neighbour.
Russia is focussed on driving Ukrainian forces out of Luhansk and Donetsk provinces in the Donbas, where Moscow-backed separatists have been fighting Kyiv since Russia's first military intervention in Ukraine in 2014.
Ukrainian troops describe intense artillery barrages on residential areas, especially around Lysychansk, the last holdout city in Luhansk.
"The Russians are strengthening their positions in the Lysychansk area, the city is on fire," Luhansk Governor Serhiy Gaidai said on Telegram. "They attacked the city with inexplicably brutal tactics."
Rodion Miroshnik, ambassador to Russia of the pro-Moscow self-styled Luhansk People's Republic, told Russian television, "Lysychansk has been brought under control," but added: "Unfortunately, it is not yet liberated."
Russian media showed video of Luhansk militia parading in Lysychansk streets waving flags and cheering, but Ukraine National Guard spokesman Ruslan Muzychuk told Ukrainian television the city remained in Ukrainian hands.
"Now there are fierce battles near Lysychansk, however, fortunately, the city is not surrounded and is under the control of the Ukrainian army," Muzychuk said.
Reuters could not independently verify the battlefield reports.
Oleksiy Arestovych, an adviser to Ukrainian President Volodymyr Zelenskiy, said Russian forces had finally crossed the Siverskiy Donets river and were approaching the city from the north.
"This is indeed a threat. We shall see. I do not rule out any one of a number of outcomes here. Things will become much more clear within a day or two," he said.
"The more Western weapons come to the front, the more the picture changes in favour of Ukraine." Ukraine has repeatedly appealed for more weapons from the West, saying its forces are heavily outgunned.
Troops on a break from the fighting in Konstyantynivka, a market town about 115 km (70 miles) west of Lysychansk, said they had managed to keep the supply road to the embattled city open despite Russian bombardment.
"We still use the road because we have to, but it's within artillery range of the Russians," said one soldier as comrades relaxed nearby, munching on sandwiches or eating ice cream.
"The Russian tactic right now is to just shell any building we could locate ourselves at. When they've destroyed it, they move on to the next one," he said.
Far from the eastern fighting, Russia said it had hit army command posts in Mykolaiv near the vital Black Sea port of Odesa, where the mayor on Saturday had reported a number of powerful explosions.
"The Russian occupiers are launching systematic rocket attacks in the direction of Mykolaiv,” Ukraine's general staff said on Sunday.
Ukrainian authorities said another missile slammed into an apartment block near Odesa on Friday, killing at least 21 people. A shopping mall was hit on Monday in the central city of Kremenchuk, killing at least 19.