MOSCOW — A late-night barracks collapse killed 23 people and wounded at least 19 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.
The Russian defense minister, Sergei K. Shoigu, interrupted his vacation to monitor the unfolding recovery effort and to brief President Vladimir V. Putin on Sunday night. Mr. Putin on Monday expressed condolences to family members of the victims, his spokesman, Dmitri S. Peskov, told Russian news agencies.
Photographs showed the barracks, a four-story blue-and-white concrete rectangle flanked by identical buildings, with a jagged gash at its center, running from the roof to the ground floor.
The treatment of Russian military personnel is a delicate topic these days given Russia’s repeated and forceful denials that any regular duty soldiers have been sent to fight in eastern Ukraine.
Dozens of Russian citizens, including some who were known to be active duty soldiers in airborne units, have been killed in the fighting in eastern Ukraine. Although it has been impossible to deny their deaths in light of funerals around the country, the Kremlin has insisted that the fallen fighters must have been volunteers.
The heightened sensitivity may explain why Mr. Peskov felt compelled to emphasize in a statement to the Interfax news agency that Mr. Putin on Monday had ordered the defense minister “to give full medical assistance to the victims of this accident” — a point that might otherwise go without saying.
There was no mistaking the force of the government’s response to the accident, which included a search-and-rescue team of more than 150 soldiers, as well as canine units.
The Russian military has been in a state of heightened alert since the invasion and annexation of Crimea from Ukraine last year. Russian airborne units had pivotal roles in Crimea and have been part of Russia’s military activities connected to the pro-Russian insurgency in eastern Ukraine.
The base in Omsk is the Russian military’s main training center for airborne forces, which include some of the country’s most elite fighting units. They are known by the acronym V.D.V. for their formal name, which translates as air-landing troops.
They are known to be outfitted with some of the Russian military’s best weapons and equipment, including amphibious fighting vehicles and self-propelled artillery.