Baema Chilain, vice-chairman of the Chinese-controlled Tibet Autonomous Region, also said "separatists" were planning to disrupt the Olympic torch relay as it crossed Tibet, but he pledged to ensure the flame's security in the region and on its planned ascent of Mount Everest, the official Xinhua news agency said.

About 30 monks at the Jokhang Temple, one of the holiest in Tibet, shoved their way into a briefing and spent about 15 minutes telling reporters the government was lying about recent unrest. They also rejected Chinese claims that Tibet's spiritual leader, the Dalai Lama, was behind the rash of protests.

These monks will not be punished, Xinhua quoted Baema Chilain as saying.

"But what they said is not true. They were attempting to mislead the world's opinion," he said. "The facts shouldn't be distorted."

More than two weeks of unrest in Tibet and western China, including a day of violence in Lhasa on March 14, and China's response ahead of the Beijing Olympics in August have sparked international controversy.

China has hoped the Olympics will showcase the achievements of the world's fourth-largest economy and its rise as a global power, but the games are becoming a lightning rod for criticism.

"To our knowledge, some separatists from within and outside China are seeking to sabotage the Olympic torch relay within Tibet," said Baema Chilain.

"We are confident and capable of ensuring the security of the relay and taking it to the top of the peak."

The Chinese government blames the Dalai Lama and his followers for the violence and claims overall harmony, religious freedom and well-being in the Himalayan region.

Critics of China, however, say there is widespread discontent among Tibetans, including monks, who feel they are restricted religiously, their culture is being suffocated by an influx of Chinese to Tibet and they do not have sufficient autonomy.

The London-based Free Tibet Campaign said it had received unconfirmed reports from various Tibetan sources inside Tibet that three main monasteries in Lhasa -- Ganden, Sera and Drepung -- have been cut off since March 11 with no access to food, water and electricity.

"The monks in those monasteries are being starved. The reports have said that Tibetan laypeople have attempted to bring food to the monasteries but have been denied access," it said.

Baema Chilain, the Tibet official, said the monks at the Ganden, Sera and Drepung monasteries as well as the Jokhang temple were being "temporarily confined to the premises as the authorities were investigating allegations that some of them led or participated in the violence".

More than a dozen Western and Asian diplomats are to leave for Lhasa on Friday as part of a public relations exercise launched by China to limit the damage from the Tibet crisis, envoys said. They will visit for two days but have not been told what the itinerary would be.

Prosecutors had issued arrest warrants for 30 people in connection with the Lhasa violence, Baema Chilain said, adding they were sought for "endangering national security and committing severe criminal offenses".

So far, 414 people had been detained, mostly ethnic Tibetans but also some members of the Han majority ethnic group that makes up more than 90 percent of China's population, he said.

The government would provide interest-free or government subsidised loans to help businesses damaged in the Lhasa violence, Xinhua reported.