At least four civilians were killed and several wounded in Russian shelling of the city of Kharkiv in northeastern Ukraine on Thursday, local authorities said.
"The occupiers are shelling the regional centre again," Kharkiv region Governor Oleh Synehubov wrote on the Telegram messaging app, urging residents to go to shelters.
Kharkiv, Ukraine's second biggest city, had been relatively quiet in recent days as Ukrainian forces regained territory around it and pushed back Russian troops.
The city restarted its metro service on Tuesday and asked the hundreds of people who had used the underground as a bomb shelter to free up the train carriages.
But many said they were still too scared to return home and a Reuters correspondent in Kharkiv on Thursday reported hearing explosions as Russian forces dug in and maintained control of their positions in villages north of the city.
In the neighborhood of Pavlove Pole, local resident Maryna Karabierova said the crump of artillery had been growing recently but many people had become inured to the sounds of war after three months.
Karabierova, 38, said she had fled to Poland and Germany after the Feb. 24 invasion but later returned to Kharkiv.
"It’s loud here but it's home at least," she said as another blast was heard nearby. "It (explosions) can happen at any time, at night, during the day, this is what life is here."
(Reporting by Mari Saito in Kharkiv and by Natalia Zinets in Kyiv, Editing by Timothy Heritage)