Updated with new death toll at 6.45pm.

A Russian missile strike on Monday hit a crowded mall in the eastern Ukrainian city of Kremenchuk, Ukraine's President Volodymyr Zelensky said, killing at least 10 and injuring dozens more.

"The occupiers fired missiles at a shopping centre where there were over a thousand civilians. The mall is on fire, rescuers are fighting the fire. The number of victims is impossible to imagine," Zelensky wrote on Telegram. 

A video shared by Zelensky showed the mall engulfed in flames with dozens of rescuers and a fire truck outside.  

The Ukrainian president's deputy chief of staff, Kyrylo Tymoshenko, said on Telegram that there were around 20 wounded so far, with nine in "serious condition". 

Poltava region governor Dmytro Lunin denounced the attack as a "war crime" and "crime against humanity", saying it was a "cynical act of terror against the civilian population". 

UN slams 'deplorable' Russian strike on mall                                    

United Nations Secretary-General Antonio Guterres's office condemned as "totally deplorable" Russia's deadly attack Monday on a crowded mall in central Ukraine.

Kremenchuk, the town where the missile strike occurred, had so far been spared direct hits in the conflict, Guterres spokesman Stephane Dujarric said at a daily press briefing.

"Any attack that hits a shopping mall is totally deplorable," the UN official said.

"We once again stress that the parties are obliged under international humanitarian law to protect civilians and civilian infrastructure," he added.

Dujarric stated he was not able to confirm the strike's death toll. 

But Dmytro Lunin, the governor of the Ukrainian region where the missile attack occurred, said at least 10 people were killed and more than 40 injured, and warned the toll was likely to rise.