Orthodox monks have been trying to reach the cave

The group calls itself the "True Russian Orthodox Church". Members are waiting for the end of the world, which they are expecting to happen next May.

They say they have enough food and water to last out the winter, as well as large quantities of petrol.

The cult leader did not join them, and has been arrested by police.

Russian television showed pictures of black-robed Orthodox monks scaling down into a snow-covered gully in a forest in the Penza region, about 650km (400 miles) south-east of Moscow.

Cult leader Pyotr Kuznetsov is undergoing psychiatric examination

Those inside are believed to include four small children.

Cult members say they have hundreds of canisters of petrol and threatening to ignite them if the authorities try to force them out.

The group was founded by a former engineer, Pyotr Kuznetsov, who had fallen out with the Russian Orthodox Church.

He is thought to have ordered his followers into the cave but did not join them.

He is now in custody and is undergoing psychiatric examinations.