Foreigners have effectively been barred from travelling to the region, China has strangled the flow of information from there, and police are harassing journalists seeking to report on related protests in neighbouring provinces.

The difficulty in getting reliable information from the restive areas also stems partly from topography.

Perched high up on the Himalayan plateau, Tibet's ancient culture has long been isolated from the world and intrepid journalists cannot simply walk or drive into the region.

'This has been extremely difficult to cover and I think every foreign correspondent in Beijing is scrambling and unable to do what they want - go to (Tibet's capital) Lhasa and report first-hand,' said Melinda Liu, Newsweek magazine's bureau chief and president of China's foreign correspondents' club.

The restrictions have reduced journalists to cold-calling numbers on Tibet's rickety phone system for vague snippets of information.

Most of those who answer phones have little useful information, having been confined to homes and workplaces through the weekend by a police curfew, or are simply too scared to talk.

However persistent phone calls do pay off, with a gradual picture emerging of a massive security presence in Lhasa and elsewhere, with Chinese forces shooting at protesters resulting in deaths.

China's police apparatus has added to the difficulty of reporting on the Tibet unrest, or protests in neighbouring Sichuan, Gansu and Qinghai provinces that are also part of the wider ethnic Tibetan heartland.

A journalist seeking access on Monday to the town of Xiahe in Gansu province, where large protests by Tibetan monks were dispersed with tear gas, according to activists, said roads to the area from the provincial capital of Lanzhou were lined with checkpoints.

Foreigners were being denied bus and train tickets, he said. Those that had made it on buses were being pulled off by police, he said.

Hotels in Tongren, in neighbouring Qinghai province also were refusing rooms to foreigners, he said.

Foreigners living in these areas are sometimes too scared to talk, fearful that speaking out against the crackdown may land them in trouble with authorities.

Meanwhile, China's media censorship arm has been working overtime.

Access to Youtube in China was blocked over the weekend after clips of the Lhasa riots were uploaded to the video-sharing site.

Yahoo's news page, which has carried foreign press reports of the unrest, also could not be called up on Monday. The state-run press carries only the official Chinese government-approved versions of events.

'It's been a nightmare for a journalist. There have been wildly different accounts in terms of the numbers of deaths and it's been impossible to pin down the truth,' said Mr Liu.

The basic facts are not in dispute: protests led by Buddhist supporters of Tibetan spiritual leader the Dalai Lama last week were met by a security response, triggering an escalation into deadly full-scale riots.

But that's where the clarity ends. Tibet's government chief Qiangba Puncog said on Monday 13 civilians were killed by rioters.

Free-Tibet groups, however, say up to 100 may have died, many killed by security forces.

Chinese propaganda tells of rampaging bloodthirsty mobs killing the innocent.

Tibet activists stoke fears of a bloody Chinese crackdown.

'The Chinese say the world is not reporting accurately, but at the same time they don't allow people to go in and report it,' said Tsering Wangdu Shakya, an ethnic Tibetan professor at the University of British Columbia. -- AFP