Human error could be to blame, either through the failure of equipment or violations of coal mining regulations, a source close to the investigation told RIA-Novisti.

Russian Prime Minister Vladimir Putin has called for an investigation into the explosion in the Siberian coal mine, which is believed to have trapped another 38 miners.

About 200 rescuers, who have been frantically searching for survivors since the weekend, managed to examine only 1.5 kilometres of the mine by late Monday, Emergency Situations Minister Sergei Shoigu said Tuesday. His ministry was unable to immediately provide an updated figure.

Shoigu, who accompanied Putin to the scene of the disaster Tuesday, has warned that the trapped workers were unlikely to survive past Wednesday morning because of rising flood waters and a broken anti-flooding system, according to the Moscow Times.

A total of 359 miners were working Saturday night when a first explosion tore through a tunnel at 11:54pm, emergency workers said. There was a second blast four hours later as rescuers sought to assist miners caught in the first blast, they said.

No serious safety violations have been recorded at the mine over the past 16 months, according to an Energy Ministry report cited by Tayga.info on Tuesday.