By Kathryn Westcott
Attempts are being stepped up in Russia to end a stand-off between the authorities and members of a doomsday religious group who have barricaded themselves inside a cave in a remote region and are threatening to blow themselves up.
Pressure is mounting on the authorities to act because of concerns for four children - one as young as 18 months old - who are among the 29 members of a splinter group of the Russian Orthodox Church.
Orthodox monks have been trying to reach the cave
The group retreated to the man-made cave in a wind-swept, snow-covered ravine in the Penza region, some 640km (400 miles) from Moscow, almost a month ago.
They said they would await the end of the world there, adding that they would kill themselves if moves were made to force them from their hideout.
On Wednesday, it was reported that the group's leader, self-declared prophet Pyotr Kuznetsov - who did not go into hiding with his followers - had visited the site to try to win the release of the children.
The drama is the latest incident in the country's troubled relations with what the authorities describe as "cults" or "sects" but some Western observers prefer to call "new religious movements".
Over the past decade, attempts have been made to restrict foreign or foreign-influenced groups.
Post-communist Russia initially gave religious creeds free rein, sparking an influx of foreign evangelists and missionaries throughout the 1990s. Religious groups such as the Jehovah Witnesses - present in the Soviet Union for decades - were joined by numerous other groups, such as Scientologists, Moonies and Krishna devotees.
Cult leader Pyotr Kuznetsov is undergoing psychiatric examination
This influx led to outcries in some quarters that Russia's moral fibre and even its national security were at risk from such groups.
"In the 1990s, there was a coming together of conservative forces, politicians, authorities within the Orthodox Church and the media in a kind of campaign against foreign groups," says James T Richardson, an expert in new religious movements at the University of Nevada.
He told BBC News that this campaign was partly responsible for the introduction of a 1997 religion law, which enshrined Orthodox Christianity as the country's predominant religion. The law pledges respect for Buddhism, Islam and Judaism, which are called traditional religions, but places restrictions on other groups.
The Penza incident has prompted calls from some quarters for the authorities to act against such "home-grown" groups.
So far, however, there appears to have been sympathy for the Penza group from members of the Orthodox Church.
Monks and priests have scaled down ropes to try to coax the faithful out of their dug-out.
One local priest, Father Georgy, in an interview with Russian television, described them as "ordinary Christians."
Marat Shterin, a sociologist of religion at Kings College London, says: "The Russian Orthodox Church tends to be quite anti-sectarian, but on this occasion there seems to be a degree of understanding that while this manifestation of millenarian beliefs - belief that we live in 'the end time' - is extreme, some of the group's views are shared by many within the Church."
He says that millenarian beliefs are fairly widespread in Russian Orthodoxy, both within the formal structures of the Church and outside it.
"What they all share is a sharply dualistic view of the world, according to which salvation in these end times is only possible within and through the Church, while the world outside is evil and doomed to imminent destruction.
"However, some of them feel that the official Church does not live up to its salvationist mission and they get attracted to new prophecies and prophets who claim the failing church is in itself a sign of the end of time."
Pyotr Kuznetsov declared himself a prophet several years ago, establishing a group of true Russian Orthodox believers who became increasingly opposed to the official Church.
According to one priest who has led prayers outside the dug-out, the group believes that "everything in the world is evil. Globalisation is evil".
It is not clear what the group's specific grievances are, but experts have highlighted other concerns held by local millenarian groups.
"In recent years there has been a whole movement within the Church that resisted the introduction of tax and individual identification numbers and new passports, seeing these as signs of 'satanic globalisation' and tribulations leading to the end of the world," says Dr Shterin.
But, he argues that while there are a number of such groups in Russia, it is dangerous to see them all as potential "doomsday cults".
He says that many are integrated in society and more concerned with "spiritual purification and trying to conquer evil by improving the world around them".
Others, he says, have taken a more "separationist" stance and moved to relatively remote areas, while still keeping some communication with wider society.
Estimates vary as to the number of new religious groups in Russia. According to Dr Shterin there are about 300 to 400 different new religious movements, or about 1,000 local communities allied to the larger movements. This, he says, includes "older groups" such as Jehovah's Witnesses or Mormons.
One of the largest "home-grown" groups is the Church of the Last Testament in Siberia, which has some 5,000 followers. Its leader, a 46-year-old former traffic policeman, predicted that the world would end a few years ago, but the date passed without incident.
Experts argue that while "end of time" beliefs are widespread around the world, it is rare that such groups engage in violence.
The group used to live in the in the village of Nikolskoye
"There have only been about eight (violent) incidents in the past few decades," says Dr Richardson.
He also says that it is difficult to explain what exactly triggers such events.
"People who study these things have thrown up their hands and said that each situation has been so unique that it is impossible to tell what set it off.
"There are so many people that hold such beliefs but live normal lives. Somewhere, something significant happens - it could possibly be down to the way a group interacts with the authorities."
In the Penza case, it has been reported that Mr Kuznetsov told authorities that the local community had written in "some paper complaining that if we were not removed, they would complain to the authorities".
Dr Shterin stresses that the outcome depends very much on how the "wider society will react towards the group", which expects the world to end in May 2008.
"This is a very long time for a group with small children to survive in an artificial cave," he says.
"On the other hand, they could easily interpret any outside pressure as a sign of the 'end time persecution', therefore as the end of the world already unfolding."