Iran has blocked access to the popular video-sharing Web site YouTube.com, and a press rights group warned on Tuesday that Internet censorship in the Islamic state is on the rise. Internet users who tried to call up the YouTube site on Tuesday were met with the message, "On the basis of the Islamic Republic of Iran laws, access to this website is not authorized" - which appears on the numerous opposition and pornographic Web sites that the government blocks. It was not known how long the site had been on Iran's Web blacklist. The Paris-based press rights group Reporters Without Borders said YouTube had been blocked for the past five days. It also said the New York Times Web page was also blocked since Friday and that the English site of the online encyclopedia Wikipedia was blocked from Friday to Sunday.