Censors in China blocked access to YouTube and Google News on Sunday, along with other news outlets carrying images and video of protests in Tibet, which turned violent late last week.

The communist government frequently tries to control what information its citizens can access, particularly on sensitive topics such as the autonomy of Tibet. But with over 210 million Internet users in China, that job has become vastly more difficult than when the government sought to suppress reports on the Tiananmen Square protests and massacre in 1989.

Blog posts, pictures and video quickly spread over the weekend highlighting the turmoil in traditionally peaceful Tibet. Protests flared up on Friday when Chinese police and soldiers moved in to quell the demonstrations by Buddhist monks and lay persons, which they claimed were timed to disrupt preparations for the Olympic Games in Beijing this summer.

Although Western media outlets including CNN have been prevented from entering the region, images from Tibet's capital Lhasa showed burning cars and buildings, bodies in the streets, and a heavy police and military presence. Users have created montages of the photographs and uploaded them as videos to YouTube.

Tibetans have long been calling for independence from China, which took control of the region in the 1950s. Since Han Chinese moved in and took over businesses and government positions, Tibetans claim they are treated as second class citizens and humans rights abuses are frequently reported.

The Dalai Lama, Tibet's spiritual leader who was exiled from the country in 1959 and won the Nobel Peace Prize in 1989, is being blamed by the Chinese government for inspiring the protests, although he denied such accusations in a press conference on Sunday. The Dalai Lama blamed China for "intentional or unintentional...cultural genocide" in Tibet.

The lack of media access has led to much uncertainty about what is going on in Lhasa and at Buddhist monasteries outside the city where other protests are taking place. Chinese authorities claim police are not using guns and many have been wounded -- an assertion that is disputed by rights group Tibet Watch, which claims women and children have been killed by police trying to stop the riots.

China has yet to comment on the YouTube or Google News block, but users have reported the sites' homepages being redirected to a blank page. It's likely the move is a short term effort to stop the spread of information on the Tibet protests, as China has been quite tolerant of YouTube and other video sharing sites thus far.

Last month, the Chinese government backtracked on a proposal to prevent all foreign Internet video sites from operating in the country unless they agreed to government ownership. In order to balance business interests with those of the communist government, the country decided to allow all sites currently operating to continue to do so, while new video sites will come under the stricter regulations.

Google has faced censorship in China before, agreeing to remove links to information deemed subversive by government regulators. The company has defended its actions by stating that the alternative would be simply not to operate in China at all. Microsoft and Yahoo have expressed similar sentiments about operating in China.