By Quentin Sommerville
BBC News, Beijing
In most of China, YouTube has suddenly become inaccessible
China is reported to have blocked the YouTube video-sharing website because it has been carrying video of soldiers beating monks and other Tibetans.
The date and location of the footage, posted by a Tibetan exile group, cannot be ascertained.
A Chinese government spokesman would not confirm whether YouTube had indeed been blocked.
China has a history of blocking websites which carry messages it views as politically unacceptable.
In most of China, YouTube has suddenly become inaccessible.
The site has been carrying a graphic video released by Tibetan exiles, which shows hundreds of uniformed Chinese troops swarming through a Tibetan monastery - a group of troops beat a man with batons.
In another scene a group of men, including a monk, are beaten, kicked and choked, while they lie on the ground. Some have their hands tied others appear to be unconscious.
The date and locations of the footage cannot be confirmed. Beijing maintains that it dealt lawfully with last years protests in Tibet.
On Tuesday, a Foreign Ministry spokesman said that China "is not afraid of the internet". However, he was unable to confirm if YouTube had been blocked.