Tibetan monks disrupted an official news briefing at a temple in Lhasa on Thursday, shouting that Chinese authorities were lying about unrest in the Himalayan region, foreign reporters said.
The incident was an embarrassment to the Chinese government, which brought a select group of foreign reporters to Lhasa for a stage-managed tour of the city, where authorities say stability has been restored since violence broke out on March 14.
The government has also been saying security forces acted with restraint, in the face of international controversy over the unrest and China's response ahead of the Olympics in August.
A group of uninvited young monks at the Jokhang Temple, one of the most sacred in Tibet and a top tourist stop in central Lhasa, stormed into a briefing by a temple administrator.
"About 30 young monks burst into the official briefing, shouting: 'Don't believe them. They are tricking you. They are telling lies'," USA Today Beijing-based reporter Callum MacLeod said by telephone from Lhasa.
Hong Kong's TVB aired television footage of the bold outburst in front of the first foreign journalists allowed into Tibet since the violence, showing the monks in crimson robes, some weeping, crowded around cameras.
The monks said they had been unable to leave the temple since March 10, when demonstrations erupted in Lhasa on the 49th anniversary of an abortive uprising against Chinese rule that saw Tibet's spiritual leader, the Dalai Lama, flee to exile in India.
"They just don't believe us. They think we will come out and cause havoc -- smash, destroy, rob, burn. We didn't do anything like that -- they're falsely accusing us," said one monk. "We want freedom. They have detained lamas and normal people."
Wang Che-nan, a cameraman for Taiwan's ETTV, said the incident lasted about 15 minutes, after which unarmed police took the monks elsewhere in the temple, away from the journalists.
"They said: 'Your time is up, time to go to the next place'," Wang said.
Reuters was not invited on the government-organised trip.
Chhime Chhoekyapa, secretary to the Dalai Lama, said the incident made clear "that brute force alone cannot suppress the long simmering resentment that exists in Tibet".
"We are deeply concerned about the safety and well-being of the monks and appeal to the international community to ensure their protection," he said.
On Wednesday, President George W Bush encouraged Chinese President Hu Jintao to talk with the Dalai Lama.
Hu said China was willing to continue engaging in "contact and discussions" with the Dalai Lama, but he must renounce support for independence of Tibet and Taiwan, and "stop inciting and planning violent and criminal activities and sabotaging the Beijing Olympics", newspapers said on Thursday.
China has blamed the "Dalai clique" for the unrest and called him a separatist. The Dalai Lama denies he wants anything more than autonomy for his homeland and has criticised the violence.
However, in a recent interview he said the Olympics were a chance for the world to remind China of its human rights record.
"In order to be a good host to the Olympic Games, China must improve its record in the field of human rights and religious freedom," the Tibetan spiritual leader told India's NDTV news channel in an interview to be aired on Friday. "It's very logical, very reasonable."
The marches by monks in Lhasa turned within days into rioting in which non-Tibetan Chinese migrants were attacked and their property burned until security forces filled the streets.
Protests have spread to parts of Chinese provinces that border Tibet and have large ethnic Tibetan populations.
China says 19 people were killed at the hands of Tibetan mobs. The Tibetan government-in-exile says 140 died in Lhasa and elsewhere, most of them Tibetan victims of security forces.
China has poured troops into the region to keep order.
Foreign Ministry spokesman Qin Gang on Thursday again called for people involved in the Lhasa violence to turn themselves in.
"We urge those lawbreakers involved in burning, smashing and looting who are still at large to hand themselves in," he said.
Human Rights Watch said the United Nations human rights council should address the crisis in Tibet.
Human Rights Watch said Australia, the European Union, Switzerland and the United States raised human rights abuses in Tibet during a session of the U.N. Human Rights Council, but China blocked debate, backed by Algeria, Cuba, Pakistan, Sri Lanka and Zimbabwe.
"The council has not only the right, but the obligation to address the Tibet crisis," a statement quoted Juliette de Rivero, Geneva advocacy director at Human Rights Watch, as saying.
"It's scandalous that the council ends up silencing those who are trying to make sure it does its job."