Raja Pervez Ashraf, Pakistan's prime minister, has ordered YouTube to be blocked after the site "refused to heed to the advice of the government of Pakistan to remove blasphemous film from its site", a statement from his office said.
Attempts to access YouTube on Monday met with a message saying the website had been classed as containing "indecent material" and was blocked on the orders of the Pakistan Telecom Authority.
Authorities in Bangladesh have also blocked the video-sharing site indefinitely to prevent citizens from watching the video that mocks the Prophet and Islam.
Protests against the anti-Islam video continued on Monday, several of them violent, in various countries across the Muslim world.
Protests were also reported from Indonesia, Afghanistan, the Philippines, Yemen and Lebanon.
In Kabul and Jakarta, protests turned violent for the first time since the furore over the film mocking Islam first broke out last week. Hundreds of angry men clashed with police, hurled stones and shouted "Death to America".
Thousands of followers of Lebanon's powerful Hezbollah group rallied against the anti-Islam film that has provoked a week of unrest in Muslim countries worldwide, as Hassan Nasrallah delivered his first major public address in four years.
Most of the men tied headbands around their foreheads in green and yellow - the colours of Hezbollah - with the words "at your service God's prophet" written on them.
Meanwhile, more than 1,000 Tunisian security forces briefly surrounded a mosque in the capital on Monday where a Salafi leader wanted by police over clashes at the US embassy last week was meeting hundreds of followers.
The Reuters news agency reported that Saif-Allah Ben Hassine managed to escape the mosque, however.
And Libya's interior minister has sacked Benghazi security chiefs after last week's deadly attack on the US consulate in
the eastern city.
Police in Azerbaijan detained about 30 Muslim activists on Monday while preventing a protest from breaking out near the US embassy.
'Go to hell'
In Kabul on Monday, more than 1,000 Afghans protested, setting police cars and commercial storage containers ablaze on Jalalabad Road, Mohammad Ayoub Salangi, Kabul police chief, told AFP news agency.
Between 40 and 50 policemen were "very slightly wounded" by stone throwers and members of the crowd waving sticks, said Salangi.
Burning tyres sent thick black smoke streaming into the sky and stones littered the road as shopkeepers hurriedly locked up and ran away.
A police official, who gave his name only as Hafiz, said protesters also threw stones at Camp Phoenix, a US-run military base in the capital, but were later driven back.
In Jakarta, protesters hurled petrol bombs and clashed with Indonesian police outside the US embassy, shouting "America, America, go to hell" in the first violent film protests in the world's most populous Muslim nation.
Police were seen kicking or dragging away some of the protesters, while one policeman was taken away in an ambulance with his face bleeding.
Rikwanto, a police spokesperson, said that officers used tear gas, water cannon and warning shots, but did not say whether they had fired live ammunition or blanks.
Clashes in northwest Pakistan
In Pakistan, thousands of students burned US flags and chanted anti-US slogans in the main northwestern city of Peshawar.
In the nearby district of Upper Dir, adjacent to a former Taliban stronghold crushed in 2009, a protester was killed and two other people wounded in an exchange of fire with police after a similar demonstration.
Protests were also held on Monday in Yemen, where hundreds of students called for the expulsion of the US ambassador, and in the Philippines.
The outbreaks of violence were the latest eruptions of anger over the low-budget trailer made in the US and aired on YouTube that has fanned unrest around the world, leaving at least 18 people dead.
The film, entitled Innocence of Muslims, believed to have been produced by a small group of extremist Christians, has led to a week of furious protests outside US embassies and other American symbols in at least 20 countries.
Following complaints, Google is now barring access to the video in Egypt, Libya, India, Pakistan, Indonesia, and Malaysia, while the government has restricted access to YouTube, which is owned by Google, in Afghanistan.