The sect members went underground in order to "save themselves during the time of the apocalypse," which they say will come in May 2008.
The group of 29 people, including four children, have threatened to set fire to themselves if any attempt is made to force them to come to the surface. The youngest of the children is said to be less than eighteen months old.
Special forces officers with rescue dogs spent Monday thoroughly exploring the ravine where the cave is located, and a plan of action has been formulated and presented, the Russian newspaper Tvoi Den said.
"The underground shelter is three to four meters deep," said an officer. "When the sect members enter into negotiations, their voices sound as if they are coming from deep down."
The cave is said to have been divided into five cells, with one large 'room' set aside for prayers. The prayer room is also, according to the sect's founder Pyotr Kuznetsov, to be used for the eventual burial of the sect members. Kuznetsov is currently being treated for paranoid schizophrenia in an asylum in Penza, about 600 km (370 miles) southeast of Moscow.
"This shows that the sect are not planning to come to the surface in May, as Kuznetsov said. Those people knew when they went underground that it was forever," a source close to the investigation said.
Media reports say the sect's above-ground prayer room also contained a coffin, and that Kuznetsov and his followers would often sleep in it to prepare themselves for death.
"Before they went into the cave, the sect members would sleep in the coffin to prepare themselves for their unavoidable deaths. The children too," a local resident told the paper.