Thirty two people were killed by a Russian missile strike on the northern Ukrainian city of Sumy on Sunday, its acting mayor Artem Kobzar said.
"The Russians hit the city of Sumy with missiles, killing civilians," Andriy Yermak, the Ukrainian president's chief of staff, said in a post on X.
Reuters was seeking comment from Russian authorities.
Andriy Kovalenko, a security official who runs Ukraine's Centre for Countering Disinformation, highlighted that the strike came after US envoy Steve Witkoff's visit to Moscow.
"Russia is building all this so-called diplomacy ... around strikes on civilians," he wrote on Telegram.
Witkoff, US President Donald Trump's special envoy for Ukraine, held talks with Russian President Vladimir Putin on Friday in St. Petersburg about the search for a peace deal on Ukraine, as Trump told Russia to "get moving".
Russia launched a full-scale invasion of Ukraine in February 2022 and currently holds about 20 per cent of the country's territory in the east and south. Russian forces have been slowly advancing in the east of late, though missile and drone strikes now dominate the war.
Russia's defence ministry said on Saturday that Ukraine had carried out five attacks on Russian energy infrastructure over the past day in what it called a violation of a US-brokered moratorium on such strikes.
Ukraine and Russia agreed to pause strikes on each other's energy facilities last month, but both sides have repeatedly accused each other of breaking the moratorium.
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