As US President George W Bush [Images] nudged it to talk to the Dalai Lama [Images], China on Thursday added a new pre-condition for dialogue asking the exiled Tibetan spiritual leader to end activities to "sabotage" the 2008 Olympics [Images] in Beijing [Images].

Hours after Bush talked on phone with his Chinese counterpart Hu Jintao on the Tibet [Images] issue, Tibetan monks embarrassed the Communist regime by staging a protest and voicing support for the Dalai Lama in front of visiting foreign reporters in Lhasa.

While the White House claimed that Bush "pushed very hard" on the need for restraint and the need for substantive dialogue with the representatives of the Dalai Lama, Beijing emphasised that Hu, also general secretary of the ruling Communist Party of China, told his American counterpart that the 72-year-old monk must stop his "sabotage" of the Beijing Olympics before it will hold talks with him.

Hu made the demand during the conversation with Bush, who called for resumption of dialogue with the Dalai Lama, and it was repeated by foreign ministry spokesman Qin Gang in Beijing.

Hu's demand on the safe conduct of Beijing Olympics in August appeared to mark a new addition to a list of actions the exiled Tibetan leader must comply before China reopens dialogue with him on the Tibet issue, analysts said.

If the Dalai Lama is keen on talks, he should especially stop activities to "fan and mastermind" violent crimes in Tibet as well as in some other regions and end activities to "sabotage" the Beijing Olympics and accept Tibet and Taiwan as inseparable parts of China, Hu told Bush.

Meanwhile, some 30 Tibetan monks from the Jokhang Temple, one of Tibet's holiest shrines, staged a dramatic protest and voiced support for the Dalai Lama in front of visiting foreign reporters in Lhasa.

The protest, defying tight security, came as China took some of the Beijing-based foreign correspondents on an escorted tour of the riot-hit Lhasa, the Tibetan capital, media reports said.

One monk shouted, "Tibet is not free, Tibet is not free" before he started to cry, an AP journalist at the scene reported.

Foreign journalists have largely been prevented from covering the unrest, biggest since 1989. However, China on Wednesday allowed a group of reporters into Lhasa for a three-day escorted visit.

The visit to Lhasa is the first by foreign journalists since violent pro-independence protests erupted there on March 14 and spread to neighbouring provinces like Sichuan, Gansu and Qinghai.

US National Security Advisor Stephen Hadley said Bush had urged Hu to restart the negotiations with the representatives of the Dalai Lama and address the grievance of the people in Tibet.

So far, six rounds of informal talks have been held between Beijing and the representatives of the Dalai Lama on the Tibet issue. However, no concrete progress has been reported.

At the same time, Hu told Bush that the recent riots in Lhasa were "by no means peaceful demonstrations or activities of non-violence as claimed by the Dalai Lama clique, but were undisguised serious and violent crimes."

Justifying the Chinese action to quell the unrest, Hu said, "No responsible government would sit by and watch when faced with this kind of violent crime, which gravely violated human rights, seriously disrupted social order and seriously endangered the safety of public life and property."

Hadley also denied that Hu brushed off Bush on Tibet.

"It was a very lengthy exchange. And it was well prepared, and you got a good flavour of it in the release that was issues by Beijing's authorities. It was a serious conversation on really all of the issues," Hadley said.

The Chinese Foreign Ministry, meanwhile, insisted that "Tibet is an internal issue. China firmly opposes any country's interference in Tibet affairs and China's internal affairs."

"We request the relevant countries to respect our sovereignty and territorial integrity and extensively recognised international laws and not to facilitate the Dalai clique and his separatist activities," the ministry spokesman said.

China, he said, had the "determination and competence" to safeguard its sovereignty and territorial integrity.

The worst-ever anti-China protests since 1989 in Lhasa began on March 10 and spread to neighbouring regions.

China says 20 people were killed by rioters. The Tibetan government-in-exile maintains that about 140 people have been killed in a crackdown by Chinese security forces.