China has blocked a range of internet sites in the runup to the 20th anniversary of the government crackdown of demonstrators in Tiananmen Square, AFP reported. Microsoft confirmed that several of its flagship sites, including Hotmail.com and the new search engine Bing.com have been blocked in China. The crackdown has also extended to several prominent social networking and blogging sites such as Twitter, Flickr, WordPress and Blogger. Video sharing site YouTube has been blocked in China since March. US-funded group Freedom House said the government is blocking social networking sites such as Twitter as they “provide a means for people to circumvent government control and mobilize dissent.” The Foreign Correspondents’ Club of China has detailed several incidents in which foreign journalists were prevented from reporting at Tiananmen Square and sources were harassed.