In the northern Indian town of Dharamsala, where the Tibetan government-in-exile has its headquarters, posters threatening to kill the Dalai Lama have appeared. They say he and his followers in India will face death if they do not leave the country.
Police suspect a Tibetan cult, Shugden, is behind the threats against the Dalai Lama, who fled to Dharamsala from Tibet in 1959, and have tightened security around him.
The New Kadampa Tradition (NKT) branch of the Shugdens, established by Kelsang Gyatso in 1991, has its headquarters in Britain. For some years relations between it and the Dalai Lama have been strained.
The cult worships a 350-year-old wrathful Tibetan deity, Dorje Shugden, often depicted wearing a necklace of 50 severed human heads and having four fangs. With three blood-red eyes he is a sword-wielding warrior figure, riding a snow lion through a sea of boiling blood.
His followers consider themselves guardians of Tibetan Buddhism, and some have described them as the Taliban of Buddhism because of their extremism.
Shugdens from the Gelukpa (Yellow Hats) sect do not like the Nyingmapa (Red Hats) sect, and consider it a sin even to talk to Red Hats or touch their religious works. They have branded the Dalai Lama, 67, a traitor to the Yellow Hats for befriending other branches of Buddhism.
Kelsang Gyatso and his followers in NKT accuse the Dalai Lama of selling out Tibet by promoting its autonomy within China rather than outright independence, of expelling their followers from jobs in Tibetan establishments in India, and of denying them humanitarian aid pouring in from Western countries.
The Dalai Lama says Shugdens pose a serious threat to Tibetan unity in exile. He has urged Tibetans not to worship Dorje Shugden, saying it fosters religious intolerance and turns Buddhism into a cult of spirit worship.
Many followers of the Dalai Lama believe that the Shugdens have links with Chinese intelligence, and suggest China is exploiting the controversy to undermine the Dalai Lama's influence and weaken support for Tibet's independence.
The chairman of the Tibetan parliament, Toma Jugney, said: "It's a deliberate attempt to create differences, not just between Indians and Tibetans, but amongst Tibetans too."
However, he did not say the cult was behind the death threats.
In September in Kathmandu, NKT members held a news conference at which they said: "The Dalai Lama and his soldiers in Dharamsala are creating terror in Tibetan society by harassing and persecuting people like us. We cannot take it lying down for long."
However, an official who handles Tibetan affairs in India's Home Ministry in New Delhi said: "We don't think that there is any Chinese conspiracy behind this death threat against the Dalai Lama.
"Probably it is fallout from infighting among the exiled Tibetans. However, we have beefed up the security cover around the Tibetan leader."