A Russian missile attack on Ukraine's southern city of Kryvyi Rih on Wednesday killed six people and injured 11 others, President Volodymyr Zelenskiy said.

"Every day and every hour, Russian terror proves that Ukraine, together with its partners, should strengthen air defences," he said on the Telegram messaging app.

Video shared by Zelenskiy showed firefighters battling blazes and rescuers heaving a block of concrete in the ruins. One man was shown being carried out of the rubble on a stretcher.

An administrative building and an apartment block were damaged, Ukraine's southern military command said. REUTERS