Three Russian missiles slammed into the heart of the central Ukrainian city of Vinnytsia on Thursday, killing 12 people including a young child and wounding 25, the State Emergency Service said.
National police chief Ihor Klymenko, citing preliminary information, said an office block had suffered a direct hit and nearby residential buildings were damaged, setting off a huge fire.
"There are wounded and dead, among them a small child," Ukrainian President Volodymyr Zelenskiy wrote on the Telegram messaging app. "What is this, if not an open act of terrorism?"
The Russian defence ministry did not immediately comment on the reports from Vinnytsia. Russia, which invaded Ukraine on Feb. 24, has denied deliberately targeting civilians in what it calls a special military operation.
Vinnytsia lies about 200 km (125 miles) southwest of the Ukrainian capital Kyiv and is far from the main frontlines in eastern and southern Ukraine.
The strike hit the car park of the nine-storey "Yuvelirniy" office block at around 10.50 a.m. (0750 GMT), the State Emergency Service said.
It posted photographs showing grey smoke rising from the twisted remains of burnt-out cars and smouldering rubble in Vinnytsia. One photograph showed an abandoned, overturned pram lying on the street.
Video footage posted on Telegram by Oleksiy Goncharenko, a Ukrainian politician, showed thick black smoke billowing out of a tall building.
(Reporting by Pavel Polityuk and Max Hunder, Editing by Timothy Heritage)