Pakistan blocked access to YouTube Monday after the video sharing website failed to take down an anti-Islam film that has sparked furious protests across the Muslim world.
Attempts to access YouTube 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.
Two protesters died in Pakistan on Monday as the backlash against the film spread across the region and angry demonstrators clashed with police, hurling stones and shouting: "Death to America."
Protests also took place in Afghanistan, Indonesia, the West Bank, the Philippines and Yemen in the latest eruptions of anger over the low-budget trailer aired on YouTube that has now led to the deaths of at least 19 people.
The movie entitled "Innocence of Muslims," believed to have been produced by a small group of extremist Christians, has sparked a week of furious protests outside US embassies and other American symbols in at least 20 countries.
In Pakistan, thousands of students burned American flags and chanted anti-American slogans in the northwest city of Peshawar, where Osama bin Laden kept a home during the 1980s jihad against Soviet troops in adjacent Afghanistan.
In the nearby district of Upper Dir, next to to a former Taliban stronghold crushed in 2009, a protester was killed and two others wounded in a shootout with police.
The crowd of about 800 people set fire to a magistrate's house and the local press club. In Karachi, Pakistan's biggest city, another demonstrator died after being shot in the head during clashes with police near the US consulate on Sunday.
Around 500 angry protesters in the eastern Pakistani city of Lahore tried to reach the US consulate but were driven back by police with tear gas.
In neighbouring Afghanistan, protests turned violent for the first time when more than 1,000 Afghans protested in Kabul, setting police cars and commercial storage containers ablaze, police told AFP.
Between 40 and 50 policemen were "very slightly wounded" by stone throwers and members of the crowd waving sticks, said Kabul police chief Mohammad Ayoub Salangi.
A police official, who gave his name only as Hafiz, said protesters also threw stones at Camp Phoenix, a U.S.-run military base in the capital, but were later driven back.
Google has barred access to the video in Egypt, India, Indonesia, Libya and Malaysia, while the government has restricted access to Google-owned YouTube in Afghanistan.
The Pakistan Telecom Authority on Monday said it had blocked 934 "anti-Islam websites" on the Internet and over 650 video postings, or URLs, on YouTube.
The move came after the Pakistani Supreme Court ordered the blocking of "all anti-Islamic blasphemous videos on YouTube, including the recently launched anti-Islamic film that has sparked protests across the Muslim world".
Prime Minister Pervez Ashraf also ordered the authorities to "block the services of You Tube with immediate effect" over blasphemous material.
In Jakarta, protesters hurled petrol bombs and clashed with Indonesian police outside the US embassy shouting "America, America go to hell", as demonstrations in the world's most populous Muslim nation turned violent.
Police were seen kicking or dragging away some of the protesters, while one policeman was taken away in an ambulance with his face bleeding.
Many of the protesters were supporters of hardline Islamic groups and were dressed in identical white Muslim garb, an AFP reporter saw.
The capital's police chief Untung Rajab said 11 policemen and a protester were injured and taken to hospital, and that four protesters were arrested.
The fresh violence came a day after the head of the Shiite Muslim movement Hezbollah, blacklisted in the United States as a terrorist group, called for a week of protests.
Hassan Nasrallah described the film as "the worst attack ever on Islam" – worse than "The Satanic Verses" by British author Salman Rushdie, who has been under an Iranian fatwa calling for his murder since 1989.
"The whole world needs to see your anger on your faces, in your fists and your shouts," he said in a televised speech broadcast just hours after Pope Benedict XVI ended a historic three-day visit to Lebanon.
Al-Qaeda in the Arabian Peninsula has also demanded violence against US diplomatic missions in the Middle East and Africa, and on US interests in the West.
The unrest began in Cairo, where protesters stormed the US embassy last Tuesday, replacing the Stars and Stripes with an Islamic banner.
Hours later the U.S. consulate in Libya's eastern city of Benghazi came under sustained attack, with four Americans killed, including ambassador Chris Stevens.
Mass demonstrations after the main weekly Muslim prayers on Friday saw 11 protesters killed as police battled to defend US missions from mobs in Egypt, Lebanon, Sudan, Tunisia and Yemen.
The United States has deployed counter-terror Marine units to Libya to protect the Tripoli embassy and stationed two destroyers off the North African coast.
It has also sent a Marine unit to protect the US embassy in Yemen, where police shot dead four protesters and wounded 34 others on Thursday as a mob breached its perimeter.
Hundreds of Yemeni students demonstrated on Monday calling for the expulsion of the US ambassador and condemning the Marines' deployment, an AFP reporter said.
The United States has evacuated all non-essential staff and family members from Sudan and Tunisia and warned US citizens against travel to the two countries.
And in Afghanistan, two U.S. Marines died and six U.S. fighter jets were destroyed when Taliban fighters on Friday stormed a giant airfield to avenge the anti-Islam film.