MOSCOW — A late-night barracks collapse killed 23 people and wounded at least 22 others in south-central Russia, as soldiers at a training center for airborne forces were crushed in their beds by a cascade of concrete and metal, the Russian Defense Ministry said on Monday.

Officials announced the death toll Monday morning after finishing an all-night search-and-rescue operation at the barracks, on the base of the 242nd Airborne Training Center in Omsk, a regional capital in southwest Siberia about 70 miles from the border with Kazakhstan.

A Defense Ministry spokesman, Maj. Gen. Igor Konashenkov, told Russian news agencies that officials had accounted for all other personnel on the base.

The cause of the collapse was unclear, and officials said an inquiry was underway, including a criminal investigation by military prosecutors. Witnesses reported that there was no explosion before the collapse and that the barracks had no gas, ruling out a common cause of building accidents.