At least 12 people were killed and 49 hospitalised, including six children, as a result of shelling in Ukraine's southeastern city of Zaporizhzhia, the region's governor said on Sunday.

A nine-storey building was partially destroyed overnight, five other residential buildings levelled and many more damaged in 12 Russian missile attacks, said Oleksandr Starukh, the governor of the Zaporizhzhia region.

"There may be more people under the rubble," Starukh said on the Telegram messaging app. "A rescue operation is underway at the scene. Eight people have already been rescued."

City official Anatoliy Kurtev had said earlier at least 17 people were killed when missiles hit a high-rise apartment complex and buildings.

Reuters could not independently verify the reports.

The city is about 125 km (80 miles) from a Russian-held nuclear power plant that is Europe's largest. Kyiv and Moscow have blamed each other for shelling at the Ukrainian-operated facility, which has damaged buildings and threatens a catastrophic nuclear accident.