BEIJING (Reuters) - Chinese authorities have launched mass arrests of Tibetans in Lhasa for interrogation about the fiercest anti-Chinese uprising for decades, a Beijing-based source told Reuters on Wednesday.

President George W. Bush urged Chinese President Hu Jintao by phone to open dialogue with the exiled Dalai Lama. Hu said China would not talk to the man it accuses of fomenting deadly riots and trying to sabotage the Beijing Olympics.

The province of Qinghai, hundreds of kilometers (miles) from Lhasa, was the latest area to see unrest. Ethnic Tibetans staged a sit-down protest after police stopped them from marching, said the Beijing-based source who had spoken to residents.

“They (police) were beating up monks, which will only infuriate ordinary people,” the source said of the protest on Tuesday in Qinghai’s Xinghai county.

A resident confirmed the demonstration, saying paramilitaries had dispersed the 200 to 300 protesters after half an hour, armed security forces had filled the area and that workers had been kept inside their offices.

The Tibetan uprising and China’s response are at the centre of an international storm ahead of the Olympics in August.

The head of the European Parliament on Wednesday questioned whether European leaders should attend the opening of the Games and invited the Dalai Lama, the exiled leader of Tibetan Buddhism, to address the EU legislature on events in Tibet.

The unrest began with peaceful marches by Buddhist monks in Lhasa more than two weeks ago. Within days, riots erupted in which non-Tibetan Chinese migrants were attacked and their property burned until security forces filled the streets.

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.

Protests have spread to parts of Chinese provinces which border Tibet and have large ethnic Tibetan populations.

The Beijing-based source said authorities were now rounding up Tibetans in Lhasa in the wake of the unrest.

“It’s very harsh. They are taking in and questioning anyone who saw the protests,” the source said. “The prisons are full. Detainees are being held at prisons in counties outside Lhasa.”

The Dalai Lama has lived in exile in India since fleeing Tibet in 1959 after a failed uprising against Chinese rule. He denies masterminding the latest demonstrations.

BUSH TALKS TO HU

U.S. President George W. Bush telephoned Chinese President Hu Jintao on Wednesday, a White House spokeswoman said.

“The president raised his concerns about the situation in Tibet and encouraged the Chinese government to engage in substantive dialogue with the Dalai Lama’s representatives and to allow access for journalists and diplomats,” she said.

Hu asserted that the Dalai Lama was behind the violence and “efforts to disrupt the Beijing Olympics”, and so Beijing could not conduct talks, according to a Chinese government Web site.

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Hu, former Communist Party chief in Tibet, crushed unrest there in the late 1980s. He defended the latest crackdown.

“Any responsible government, faced with such violent criminal acts that are a serious violation of human rights, that seriously disrupt social order and seriously jeopardize people’s lives, property and safety, would not just sit there and watch,” the Web site paraphrased him as saying.

International calls have grown for China to show restraint in its response to the unrest, but few urge an outright boycott of the Beijing Games.

The speaker of the Tibetan parliament in exile said the Games should go ahead but be used to pressurize Beijing.

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Beijing-backed scholars vowed to press ahead with “patriotic education” of the rebellious monks in Tibet’s monasteries.

“The purpose of patriotic education is because the Dalai clique has been trying hard to disrupt development in Tibet and disrupt the normal practices of Tibetan Buddhism,” Dramdul, who heads the Religious Studies Institute at the China Tibetology Research Centre in Beijing, told a news conference.

LHASA RAILWAY

Protests continued elsewhere. A Tibetan man tried to set himself on fire in eastern India, as Indian security forces stopped him and hundreds of other marchers from entering Sikkim state, which borders China, according to a local police officer.

A small group of foreign and Chinese reporters arrived in Lhasa on Wednesday, tightly supervised by Chinese authorities.

The Dalai Lama expressed surprise. “Really? Then very good, but it should be with complete freedom -- only then you can assess the real situation,” he told reporters in New Delhi.

In a letter circulated by the Washington-based International Campaign for Tibet, a Lhasa resident described tight controls on religion and resentment over the influx of Han Chinese residents since a rail link was built to the remote, mountain region.

Lhagpa Phuntshogs, head of the China Tibetology Research Centre, accused protesting monks of wanting to restore the serfdom of Tibet’s pre-communist past.

“What do they want? I think it’s very clear that they want to try to restore the old theocracy in Tibet. The separatist elements are not happy with the end of theocracy in Tibet ... and they are not happy with the end of backwardness in Tibet.”