More than two dozen doomsday cult members settled in a snowy forest near the Volga River to await the end of the world, which their leader says will come in spring.
The cult members have threatened to blow themselves up with about 400 liters (100 gallons) of stockpiled gasoline if authorities forced them out of what officials described as a cave or bunker near the village of Nikoskoye, about 400 miles (640 kilometers) southeast of Moscow, said regional spokesman Yevgeny Guseynov.
"Any forceful action is dangerous," Guseynov said, but he added that doctors and rescuers were nearby and trying to coax the cult members to leave.
Self-declared prophet Pyotr Kuznetsov, who established his True Russian Orthodox Church after he split with the official church, blessed his followers before sending them into the cave earlier this month, but he did not join them himself.
He was undergoing psychiatric evaluation Friday, a day after he was charged with setting up a religious organization associated with violence, Guseynov said.
Russian state television broadcast footage of Kuznetsov, a thin, bearded man, speaking at the clinic where he was being examined.
He said cult members initially aimed to dig out small refuges where they could spend a day or two in prayer, but that later "we had the idea of making a big dugout for all of us to go to and stay there, just to avoid acts of hooliganism by the local population," according to the footage.
The 29 people - including four children, one only 18 months old - had stocked the cave with food and other supplies.
Kuznetsov said in the footage, shown on the Rossiya channel, that he had not gone into the cave himself because "I had to meet others who were yet to arrive."
On Thursday, black-clad Russian Orthodox monks carefully descended into snow-covered gully to try to make contact with the cult, but members refused to speak with clergy. They were exchanging letters with Kuznetsov, however, and were in contact with doctors and officials, who promised food or medical supplies if needed.
Most of the adults in the cave were women, Russian newspaper Izvestia reported.
Kuznetsov, 43, a trained engineer who comes from a deeply religious family, declared himself a prophet several years ago, left his family and settled in Nikolskoye. He began writing books, borrowing from a mixture of established beliefs, and visited monasteries both in Russia and Belarus, recruiting followers, Guseynov said.
Kuznetsov said his group believed that, in the afterlife, they would be judging whether others deserved heaven or hell, Izvestia reported Friday. Followers of his group were not allowed to watch television, listen to the radio or handle money, media reports said.
Anna Vabishchevich said her 41-year-old son, Alexander, and his wife and two teenage daughters were among the cult members. She said she was sending two relatives from Belarus to try to convince him to at least send the girls home.
She told The Associated Press that her son, a railroad worker, came under Kuznetsov's influence several years ago. He stopped eating food packaged with the universal product code - which the cult regards as the mark of the Antichrist, she said.
"My son was kind and now he is mentally ill, it's like he is hypnotized," she said between sobs.
Alexander Dvorkin of the Moscow-based independent Center of Religious Studies said Kuznetsov's followers were in serious danger and "any wrong move" by authorities could cost lives.
"Their minds are being manipulated, they are under the strong influence of their leader," Dvorkin said.
He said there were about 10 similar cults in Russia, most nominally Christian and with members living in isolation. So far, he said, authorities have done little or nothing about them.
Russian Orthodox Church spokesman Georgy Ryabov said the emergence of Kuznetsov's cult was a consequence of "the absence of a system of spiritual and moral education" in Russia.
"All Christians of Russia have to pray for them so they awaken and understand their mistake," Ryabov said.