A section of a Russian military barracks has collapsed, killing 23 soldiers, near the Siberian city of Omsk, officials say.
A further 19 servicemen were rescued. Some have been flown to Moscow for medical treatment.
All of those killed were conscripts, with some reports giving the age of the youngest victim as just 18.
Investigators are examining whether repairs carried out on the building in 2013 are linked to its collapse.
An investigation into possible negligence has been launched.
The soldiers, who were stationed at a paratrooper training camp, had just gone to bed when the wall fell down and parts of the roof caved in.
Russia's defence ministry has been quick to announce generous compensation payments for those affected, says the BBC's Sarah Rainsford in Moscow.
But the barracks collapse will be a political blow for Mr Putin, she says, as he has invested heavily in modernising the military and burnishing its image.