At least 40 workers have been confirmed dead in Saturday's methane explosion at a Siberian mine while the search and rescue operation for another seven trapped miners continues, the Itar-Tass news agency reported Sunday.

The blast tore through the Taizhina mine in the town of Osinniki in Russia's Kemerovo district early Saturday when 55 miners were working in the colliery, about 3,000 km east of Moscow, in western Siberia's coal-rich Kuzbass area.

Eight workers have been rescued but the fate of the other 7 is unknown, a duty officer with the information center of the Russian Emergency Situations Ministry was cited as saying.

Some 150 rescuers are working at a depth of about 600 meters underground, but heavy gas pollution and dense smoke at the scene of the blast seriously hindered the rescue efforts.

Specialists said the operation would not be completed until late Monday.

Investigators blamed a sharp increase of the methane content for the explosion, but they have not established why the methane rose so quickly in a short period of time, according to Valenin Simuchenkov that heads the investigation team.

Families of those killed are expected to get 50,000 rubles (US$1,754) in compensation from the regional administration, the Itar-Tass reported.

Saturday's explosion was the first major accident at the Taizhina mine, which was opened in 1998.

In September 2002, one worker at the mine was killed and two were seriously injured when the roof of a ventilation shaft collapsed during reconstruction work.

(Xinhua News Agency April 11, 2004)