KATHMANDU, April 1 (Reuters) - At least 87 Tibetan protesters were detained when they tried to storm the Chinese embassy in the Nepali capital on Tuesday in the latest crackdown on demonstrations against Beijing, police said.

Groups of Tibetans have protested in front of the United Nations office in Kathmandu and near a Chinese consular office since last month but this was the first time activists managed to get close to the main embassy building in a high security zone.

"Free Tibet... peace in Tibet," monk Tenzing Yeshi yelled as he was dragged on the road and hauled into a police truck.

Another protester Nima Dolkar, 38, said they wanted to enter the main embassy building and demand independence of Tibet.

Nepal has threatened more crackdowns if the exiles continue anti-China protests, as it considers Tibet as part of China.

On Monday, police beat pro-Tibet protesters with sticks in Kathmandu and detained more than 280 people for demonstrating against China, police and officials said.

More than 20,000 Tibetans have been living in Nepal since fleeing their homeland after a failed uprising against Beijing in 1959.

Earlier, New York-based Human Rights Watch and Amnesty International, based in London, urged Nepal to immediately restore the rights to freedom of assembly, expression and movement, by allowing Tibetans to go about their daily lives and carry out peaceful protests without fear.

"Police have further threatened Tibetan protesters with deportation, which would also constitute a serious violation of Nepal's international human rights obligations," the watchdogs said in a letter to Prime Minister Girija Prasad Koirala.

They said police had pre-emptively arrested people they believe were likely to participate in demonstrations, targeting in particular anyone they believe to be a Tibetan.

The groups said they are "particularly concerned about increasing evidence of the police's use of sexual and other forms of assault".

Nepal officials could not be immediately reached for comment.

But in the past authorities said Nepal was committed to not allowing any protests against China, which provides much-needed economic development aid to the impoverished nation. (Reporting by Gopal Sharma; Editing by Krittivas Mukherjee)

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