Valery Kuznetsov, a top local justice official, was quoted by RIA news agency as saying 22 people were injured when the two-storey building at Kurchaloi, about 60 miles from the regional capital Grozny, came down after the blast.

Many of the dead were soldiers but they included one woman.

A fire that followed the explosion was brought under control, and the scene of the blast was cordoned off. Soldiers helped emergency services well into the night to remove chunks of rubble trapping colleagues.

"We have now finished recovering dead and injured from the ruins. The figures we now have are the final ones," Kuznetsov said.

Asked if the explosion could have been caused by a Chechen separatist bomb, Kuznetsov said nothing could be ruled out, but other officials made clear it appeared to be the result of a gas explosion.