MOSCOW (AP) — The death toll in a gas explosion at an apartment building in southern Russia has climbed to two after a woman was found in the debris.

The blast on the top floor ripped through the nine-story building in the city of Shakhty, not far from the Ukrainian border, before dawn on Monday. One woman was found dead and several people have been rescued from the rubble. Two of them are in hospital in stable condition.

The Emergency Situations Ministry said rescue workers found a second victim in the rubble in the early hours on Tuesday.

Authorities are treating the incident as a gas explosion.

Emergency officials said they are expecting to finish the rescue operation by the end of the day.

Three people remain missing.