A Tibetan exile died after setting himself ablaze at a Buddhist monument in Nepal Tuesday in an apparent protest against Chinese rule over Tibet, a police official said.

Around 120 Tibetans have set fire to themselves since February 2009, mostly in China. At least 90 have died.

"A Tibetan man in his forties set himself on fire at the Bouddhanath Stupa temple in the morning. His body was badly burned," Arjun Chand, a police official in Kathmandu, told AFP.

"He was taken to the Teaching Hospital, where the doctors declared him dead," Chand said.

Chand added that police are investigating the case, the third such incident at the temple since November 2011, when the protester's life was saved.

Police official Arun Kumar Bhandari told AFP the incident occurred near a small garden at the Bouddhanath stupa, one of the holiest sites for Buddhists.

"A few passersby and some vendors tried to douse the fire by covering him with clothes but it proved futile," Bhandari said.

"The incident occurred at 7:45 am local time (0200 GMT). We are investigating about his origin, background and his motives," Bhandari said.

A small empty bottle with traces of kerosene was found near the site, Bhandari added.

Police recently tightened security and set up CCTV cameras near the temple and adjoining Buddhist neighbourhoods. Around 10 percent of the Hindu-majority nation of 26 million people are Buddhist.