Iran blocked YouTube and its owner Google over the weekend because of an inflammatory movie trailer about the Prophet Mohammed that has infuriated Muslims in many countries around the world.
The sites were blocked "because of public demand," Iran's semiofficial Mehr news agency said Monday.
"Google and YouTube continued to carry the film clip that insulted our people's sacred beliefs," the agency said, citing an unnamed source in Iran's Internet Authority.
Iran was responding to a 14-minute online trailer for "Innocence of Muslims," a once obscure film that mocks Mohammed as a womanizer, child molester and killer.
Demonstrations against the movie and the country in which it was privately produced, the United States, spread across many countries this month.
Most of the demonstrations have been peaceful, but a number have been marked by violence that has left more than two dozen people dead -- among them U.S. Ambassador to Libya Chris Stevens and three other Americans killed in an attack on the U.S. Consulate in Benghazi, Libya.
Kamran Saghafi, of the High Council for the Internet in Iran, warned Iranians not to try to access the sites.
"Internet users must voluntarily stop using those services and must not even try getting connected, even if it is just to see if they can succeed," Mehr quoted him as saying.
He said that the council was not involved in the decision to block the global Internet giants' sites, but that the action was "legal and authorized."
Mehr quoted a source in the Ministry of Technology as saying that authorities who are in charge of filtering the Internet made the decision.
Last week, Pakistan's Ministry of Foreign Affairs demanded that the United States remove the controversial movie from YouTube.
President Barack Obama and Secretary of State Hillary Clinton have disavowed the video.