At least 23 Russian soldiers have been killed and 19 injured when a military barracks collapsed near the Siberian city of Omsk, the Defence Ministry said.
Television footage showed rescue workers hauling large chunks of rubble out of the long, four-storey barracks, a training facility for paratroopers where part of the roof caved in at around 11pm (1700 GMT) on Sunday.
Whole floors had given way in the middle of the blue and white building, leaving twisted pieces of metal and concrete jutting out.
Punishing those responsible
A local Defence Ministry spokesman said a plane with medical equipment had been sent from Moscow and some of the injured were flown to the capital for treatment, according to the Reuters news agency.
The federal Investigative Committee said that one line of inquiry was the quality of repairs carried out in 2013 on the building just outside Omsk, 2,250km east of Moscow.
"I can say that all people responsible in varying degrees for this tragedy, regardless of their position or duty, will be prosecuted and will be punished," said the committee's spokesman, Vladimir Markin.
Russia has a poor safety record and a history of building collapses and transport accidents.
The Kremlin said President Vladimir Putin had sent his condolences to the families of the victims and ordered the Defence Ministry do all it could to assist those hurt.