In Kherson, abandoned by Russian troops last month, Russian forces shelled the maternity wing of a hospital, said Kyrylo Tymoshenko, Ukrainian President Volodymyr Zelenskiy's deputy chief of staff, on Telegram. No one was hurt and the staff and patients had been moved to a shelter, Tymoshenko said.
Reuters was unable to immediately verify the reports.
The Kremlin's military campaign had set out to subdue Ukraine within days of a February invasion, but its forces were defeated on the outskirts of Kyiv in the spring and forced to flee other areas in the autumn.
Putin has responded by summoning hundreds of thousands of reservists for the first time since World War Two to fight in his "special military operation".