Rescuers found one survivor Tuesday and hunted for four still missing in a Siberian coal mine, after 106 workers died in Russia's worst mining disaster since the collapse of the Soviet Union.

Smoke, pockets of gas and collapsed roofs were hampering rescue efforts in the warren of shafts nearly 300 meters underground at the wrecked Ulyanovskaya mine in the Kemerovo region, officials said.

As distraught relatives gathered outside a morgue in a nearby city to identify their dead, Emergencies Minister Sergei Shoigu told Russian television that one man had been rescued from the pit alive a day after a gas explosion devastated it.

Asked about the chances of the four still missing, he said: "We hope. We hope." He gave no details about the survivor.

Guards barred most journalists from getting within sight of the mine complex, which is surrounded by birch forests and soot-blackened snow.

President Vladimir Putin began a meeting with officials in Moscow by ordering a minute's silence for the dead miners - as well as 62 people killed overnight in a fire at an old people's home and six who died in a weekend plane crash.

"You have to do your best to investigate the reasons at the highest level... and to draw corresponding conclusions," Putin told Prime Minister Mikhail Fradkov in his first public comments on the spate of fatal accidents.

Putin said in a telegram to the Kemerovo regional governor that "this terrible tragedy at the Ulyanovskaya pit echoes in the hearts of Russians with pain".

Authorities opened an investigation into the causes of the disaster. "Initial indications are that methane or coal dust exploded, as a result of which the roof collapsed," The Federal Prosecutor-General's office said in a statement.

Authorities believed a failure to follow safety rules was the most likely cause of the disaster, the worst mining tragedy since the collapse of the Soviet Union in 1991.

Earlier, a spokeswoman for the Emergencies Ministry said 106 people were confirmed dead and the fate of four others remained unclear. Ninety-three people were brought safely to the surface.

(China Daily via agencies March 21, 2007)