At least four people have been killed and several injured by a gas explosion that ripped through a residential building in the Russian city of Yaroslavl early Tuesday, authorities said.

"Unfortunately, four bodies have been recovered. The four victims were evidently the occupants of neighbouring apartments, the walls of which were blown up," regional governor Sergei Yastrebov told news agency RIA-Novosti.

"The situation is not clear right now," Yastrebov said, adding that more bodies could be under the rubble.

A source in the emergency situations ministry told the TASS state news agency that nine injured people had been hospitalised following the  blast in the central Russian city, which damaged nearly 15 apartments.

Authorities said 550 rescuers and 130 vehicles were being sent to the scene, while a criminal inquiry has been opened to investigate whether safety regulations were breached.

Gas explosions are common in Russia. The last serious accident, in February 2012, killed 10 people in the southern city of Astrakhan and destroyed the entire side of a nine-storey building.

In December several people were killed in a similar explosion in the southern city of Volgograd.
Source: AFP