At least 13 people died and about a dozen disappeared after a dam collapsed in a gold mine in a remote Siberian settlement on Saturday, Russian authorities said.
The dam on the Seiba River in the Siberian region of Krasnoyarsk exploded and flooded several cabins where the victims lived, Russian authorities said.
Authorities said the dam had apparently been built in violation of safety rules and alleged that the authorities did not know of its existence.
Investigators said they have opened a criminal investigation into the violation of security regulations.
"As of now, there is information about 13 dead," the emergency ministry said in a statement.
In another statement, Krasnoyarsk regional authorities said 12 people had died and 13 more were missing.
Fourteen people were hospitalized, and three of them were in serious condition, the regional health ministry said.
Regional governor Alexander Uss said in televised comments that around 80 workers lived in the temporary settlement in the remote village of Shchetinkino, located south of the city of Krasnoyarsk.
The total settlement population is estimated at approximately 180.
A team of doctors, including a neurosurgeon, was sent to the scene from Krasnoyarsk, which is located about 4,000 kilometers east of Moscow.
Russian health minister Veronika Skvortsova supervised the delivery of help to the injured.
A series of senior regional officials, including Uss, prosecutors and inspectors, came to the scene of the tragedy.
The dam was built in violation of "all standards," local government chief Yury Lapshin said in televised statements.
The dam belonged to the holding company Sibzoloto, which has so far not published any comments on the incident.
More than 270 people were involved in a search and rescue operation, the emergency ministry said.
But the operation was a challenge due to the remote location.
Fatal accidents are relatively common in Russia due to lax safety rules, poor management and infrastructure of the Soviet era.
In 2009, 75 people died in a massive flood in Russia's largest hydroelectric plant in the Siberian region in Khakassia.