According to Dawn reports from Lahore, a Pakistani court Wednesday ordered authorities to block Facebook in the country over a page encouraging users to post caricatures of the Prophet Mohammed (PBUH) on the site.
Thousands of members of the social networking site have launched an online campaign demanding a boycott of Facebook over the offending page.
The depiction of any prophet is strictly prohibited in Islam as blasphemous and Muslims across the world staged angry protests over the publication of satirical cartoons of the Prophet Mohammed (PBUH) in European newspapers in 2006.
A Facebook user set up a page called "Draw Mohammed Day", allegedly inviting people to send in their caricatures of the Muslim Prophet on May 20.
Justice Ejaz Chaudhry of the Lahore High Court directed the Pakistan Telecommunications Authority (PTA) to block Facebook after a group of lawyers moved a petition in the court.
An interim order has been issued until May 31, when the court is to start a detailed hearing of the case.
A spokesman said PTA would move to implement the ban once the order has been issued by the ministry of information technology.
"We will implement the order as soon as we get the instructions," Khurram Mehran told AFP.
"We have already blocked the URL link and issued instruction to Internet service providers yesterday," he said.
Members of the social networking site told AFP on Wednesday that they were still able to access Facebook.
"We moved the petition in the wake of widespread resentment in the Muslim community against the Facebook contest," lawyer Rai Bashir told AFP.
The petition also called on the government to lodge a strong protest with the owners of Facebook, he added.
Bashir said a PTA official told the judge his organisation had blocked the page, but the court ordered a total ban on the site.
About 20 people demonstrated outside court in the eastern city of Lahore, carrying banners condemning Facebook and praising the Prophet Mohammed (PBUH).
"The court has also ordered the foreign ministry to investigate why such a competition is being held," Azhar Siddique, a representative of the Islamic Lawyers Forum who filed a petition in the Lahore High Court, told Reuters.