The government of Nepal has ordered the Kathmandu offices of two major Tibetan exiles' organisations to close down.
The Dalai Lama has had a representative in Nepal for decades
One represented Tibet's exiled Buddhist leader, the Dalai Lama, and the other a group working for Tibetan refugees.
The Dalai Lama's representative in Nepal, Wangchuk Tsering, told the BBC that a closure notice had come from an office of the home ministry.
Both groups were forced to suspend operations because they were not registered, he said.
The New-York based Human Rights Watch has urged the Nepalese authorities to allow the offices to reopen, warning that the closure of the refugee centre would leave thousands without critical support.
"The Refugee Welfare Office has been a critical safety net for tens of thousands of persecuted Tibetans," Brad Adams, the group's Asia director told Reuters.
The notice of closure was sent to Mr Tsering a week ago, but news of it has only just emerged.
Mr Tsering has suspended operations of his own mission and the Tibetan Refugees' Welfare Association, which he also runs.
The BBC's Charles Haviland in Kathmandu says it seems clear that there is politics, not just bureaucracy, behind these orders.
There has been a representative of the Dalai Lama in Nepal for 45 years without similar moves against his office.
Recently however, China, which invaded Tibet in 1950 and has ruled it ever since, appears to have been increasing pressure on its tiny neighbour Nepal, our correspondent says.
Beijing's ambassador to the country last year thanked the government for, in his words, "never allowing any anti-China activities" on Nepali soil.
The Dalai Lama, who lives in India, has long ceased visiting Nepal.
There is, however, a regular inflow of Tibetan refugees, who number about 20,000 in the kingdom.
The Washington-based International Campaign for Tibet says that if the closure of the refugees' welfare association does become permanent, there will be no organisation to help them get identity cards and prevent their forcible repatriation.