Ukrainian PM Denys Shmyhal has said defenders of the besieged port of Mariupol will fight to the end against Russian forces.
The city has not yet fallen despite a Russian ultimatum to remaining Ukrainian fighters to give up, he said.
Meanwhile President Volodymyr Zelensky said Ukraine had no intention of surrendering any territory in the eastern Donbas region.
In recent weeks Russia has focused its offensive on eastern Ukraine.
Ukraine officials say five people died after Russia shelled Kharkiv, and another two were killed in the town of Zolote.
In Mykolaiv in the south – where fighters have been holding off a Russian advance on the port of Odesa – the governor said there had been continuous rocket attacks.
In other developments on Sunday:
In his Easter address, Pope Francis called for peace in Ukraine, saying “the flexing of muscle while people are suffering” had to end
Russian and Belarusian lorries are queuing to return home via the Polish-Belarusian border after an EU deadline banning them from its territory passed
Russian officials confirmed the death of Major-General Vladimir Frolov, deputy commander of the 8th Army, the latest of several senior officers to die in the conflict