KYIV (Reuters) - Russian guided bombs struck an apartment building in Ukraine's second largest city of Kharkiv, on Saturday, killing three people, injuring 29 and prompting President Volodymyr Zelenskiy to call for more help from Kyiv's allies.

Pictures posted online showed parts of an apartment building in ruins, with windows smashed, balconies shattered and rubble strewn about a crater on the ground.

Interior Minister Ihor Klymenko put the casualty toll at three dead and 29 injured in the mid-afternoon attack. Regional governor Oleh Syniehubov said two children were among the injured and four of those hurt were in serious condition.

"This Russian terror through guided bombs must be stopped and can be stopped," Zelenskiy wrote on Telegram.

"We need strong decisions from our partners to enable us to stop the Russian terrorists and Russian military aviation right where they are."

Syniehubov said rescue work was proceeding. Other civilian targets had also been hit and public transport halted.

Mayor Ihor Terekhov said there had been four strikes.

Kharkiv lies about 30 km (20 miles) from the border with Russia. The city of about 1.3 million people has frequently been targeted in Russian attacks during nearly 28 months of war.

Russia has relied increasingly on the use of the bombs, relatively inexpensive, dropped from a distance and involving fewer risks for its forces.

(Reporting by Olena Harmash; editing by Jason Neely, Ron Popeski and Angus MacSwan)