US-based pressure group Human Rights Watch has condemned Nepal's government for using what it calls excessive force against protesting Tibetan exiles.
Recent days have seen protests by monks in Kathmandu
The Nepalese government has said in response that it has no choice but to prevent what it calls anti-Chinese protests in the capital, Kathmandu.
The protestors have regularly held rallies against Chinese rule in Tibet.
Police have often beaten them with batons, and sometimes used tear gas or inflicted head wounds, the group says.
Human Rights Watch said in a statement that one man was beaten so hard that both his feet were fractured.
The group also alleged that at least one monk was threatened with deportation to China if he took part in further protests.
It called on the government to stop the use of force and mass arrests.
"How can a government that came to power on a wave of public protests against an authoritarian regime, justify crushing peaceful protests by Tibetans?" the group asked.
Nepal's interior ministry spokesman, Mod Raj Dhotel, said the police had been told not to violate human rights.
He said Nepal could not allow any anti-Chinese demonstrations because the government follows a "one China" policy.
"We are bounded by our limitations," Mr Dhotel said.
Last week the police admitted to the BBC that they regularly received requests from the Chinese authorities not to allow such demonstrations.
BBC correspondents have also witnessed angry scuffles between Tibetan demonstrators and local Nepalese people.
Tibetan refugees living in Kathmandu have held rallies against Chinese rule in Tibet, mainly at a large Buddhist shrine or outside the United Nations country office, on at least six of the past 10 days.