Russian strikes on a crowded DIY hardware store and a residential area in the Ukrainian city of Kharkiv on Saturday killed at least four people and injured dozens, local officials said, Paralel.Az reports citing Reuters.

President Volodymyr Zelenskiy issued an impassioned plea to Ukraine's Western allies to help boost air defences to keep the country's cities safe.

Four people were killed after two guided bombs hit the DIY hypermarket in a residential area of the city, Regional Governor Oleh Syniehubov said on national television.

At least two of the dead were store employees. Forty people were injured in the attack and 16 still unaccounted for, Syniehubov said.

Kharkiv Mayor Ihor Terekhov said about 120 people had been in the hardware store when the bombs struck.

"The attack targeted the shopping centre, where there were many people - this is clearly terrorism," Terekhov said.