The accusation is the latest in a series from Chinese officials blaming recent violence and unrest in Tibet on followers of the Tibetan spiritual leader, the Dalai Lama.
"To our knowledge, the next plan of the Tibetan independence forces is to organize suicide squads to launch violent attacks," Public Security Bureau spokesman Wu Heping said Tuesday. "They claimed that they fear neither bloodshed nor sacrifice."
The prime minister of Tibet's government-in-exile quickly denied the Chinese claims, saying suicide attacks were out of the question, and Tibetan activists remain committed to nonviolence
Prime Minister Samdhong Rinpoche said Tuesday the Tibetan exile community fears the Chinese might "masquerade as Tibetans" and plan attacks to discredit the activists.
Beijing accuses the Dalai Lama and his supporters of orchestrating anti-government riots in Lhasa on March 14 as part of a campaign to sabotage the August Beijing Olympics and promote Tibetan independence.
The 72-year-old Nobel Peace Prize winner has denied the charge, condemning the violence and urging an independent international investigation into the unrest and its underlying causes.
China's campaign against the Dalai Lama has been underscored in recent days with showings of decades-old propaganda films on state television portraying Tibetan society as cruel and primitive before the 1950 invasion by communist troops.
The government has sought to portray life as fast returning to normal in the Tibetan capital of Lhasa - the scene of the deadliest violence - although its landmark Buddhist monasteries of Jokhang, Drepung and Sera were closed and surrounded by troops, tour operators said.
Monks from the three temples backed peaceful protests that broke out March 10 on the anniversary of a 1959 uprising against Chinese rule. The protests turned violent four days later and spread across a wide area of western China inhabited by Tibetans.
Beijing claims Tibet has been Chinese territory for centuries, but many Tibetans say they were essentially an independent country for much of that time.
Meanwhile, a group of Tibetan exiles and monks held a protest in front of the Chinese Embassy in Nepal's capital. Tuesday's protest was the first time that Tibetan protesters managed to get close to the main Chinese Embassy building in Katmandu's upscale neighborhood. The protesters were demonstrating in front of the United Nations or the Chinese visa office.
Police arrested all 50 protesters, who were dragged away by their feet and hands. Nepal has said it would not allow protests against friendly nations, including China.
China has ignored international calls for mediation and refuses to discuss accusations of discrimination, repression and economic disenfranchisement raised by the Dalai Lama and overseas supporters - as well as complaints over alleged shootings and other excesses in the ensuing crackdown.
Chinese state media has focused overwhelmingly on the victims of attacks, releasing the names of 14 of the 18 civilians and one police officer it says were killed in the Lhasa riots. All but one were migrants from other parts of China, among the many who have flooded into the region in recent decades.
Xinhua said 12 were killed in arson attacks. The causes of death in two other cases were undetermined, and four bodies had yet to be identified.
Authorities earlier said three other people presumably jumped from windows to escape police.
In all, authorities say 623 people, including 241 police officers, were injured in the violence.
A total of 414 suspects were in custody in connection with the March 14 riots, and another 298 people had voluntarily surrendered, state media quoted officials as saying.