OMSK, SIBERIA--Officials are searching for what caused a four-story military barracks to collapse Sunday (July 12) evening, killing 23 people and injuring at least 19 others in south-central Russia.

All of the victims were conscripts, with the youngest being 18, numerous reports said.

The Russian Airborne Troops training center's roof and wall collapsed just before 8 p.m. local time, the Russian defence ministry told reporters.

23 dead after Russian military barracks collapse in Siberia http://t.co/o3Z4G5VwEe pic.twitter.com/sEsez1Iel1

— Mashable News (@MashableNews) July 13, 2015

The concrete structure, located in Omsk, had 337 military personnel inside at the time of the collapse, according to NBC News. News reports said 19 people have been hospitalized.

A cause of the cave-in was unknown Monday (July 13) morning.

Plaster Falling

A survivor told members of the media that he knew something was wrong when chunks of plaster began falling off the ceiling Sunday night.

“Everyone started running out of the barracks and the barracks began falling apart,” Maxim Kolmakov told a local television station, Agence France-Presse reported.

He said some of the soldiers jumped from the second floor of the building onto mattresses below to save themselves.

Hundreds of rescue workers responded to the scene and spent hours combing through the rubble to search for survivors, reports said.

TUBS / Wikimedia Commons

The collapse occured in Omsk, an area located in south-central Russia.

The blue and white building served as an Airborne Forces 242^nd training center.

It was constructed in 1975 and had been renovated in 2013, according to reports.

Probe into Repair Work

Authorities say they are examining whether those building repairs were linked to the collapse.

"Errors possibly occurred during the repair, including a change in design of the building," the Tass news agency reported, citing a law enforcement source.

Further, prosecutors said the company behind the renovations had already committed safety violations during the construction of a residential building in the region of Tatarstan, AFP reported.

Reports have not identified the construction company.

Building collapses are said to be common in Russia, where the enforcement of safety regulations is lax and corruption rampant, AFP added.