Acting on an order of the Lahore High Court, the Pakistan Telecommunication Authority initially banned popular social networking website Facebook over a page featuring a contest for "blasphemous" cartoons of Prophet Mohammed.
The ban was later extended YouTube and other links.
The move also affected access to Wikipedia and Twitter, internet users said. URL or Uniform Resource Locator is the global address of documents and other resources on the World Wide Web.
"So far, two sites and about 800 URLs have been blocked to prevent access to blasphemous and sacrilegious content," Wahaj-us-Siraj, a spokesman for the Internet Service Providers Association of Pakistan said.
Siraj said that since the author of the page on Facebook featuring the blasphemous cartoons had been removed, the PTA "probably needs to go back to the Lahore High Court, and then the court could lift the ban".
The final decision in such matters would have to be made by the PTA, he said.
PTA spokesman Khurram Mehran said the authority would lift the ban only after receiving instructions from the government.
The competition for the caricatures triggered angry protests in Pakistan though internet users in bigger cities expressed disappointment at the blanket ban on popular websites.
Islam strictly prohibits the depiction of any prophet as blasphemous and Muslims all over the world staged angry protests over the publication of satirical cartoons of Prophet Mohammed in European newspapers in 2006.
Pakistan briefly banned YouTube in February 2008 over blasphemous cartoons of the Prophet Mohammed.
