The Palestinian Hamas movement on Wednesday condemned an anti-Muslim film that has sparked deadly riots, as a handful of Gazans burned U.S. flags to protest against the movie.

The low-budget film, "Innocence of Muslims," portrays Muslims as immoral and gratuitously violent. It sparked protests in Egypt and Libya, where rioters attacked the U.S. consulate in Benghazi, killing the ambassador and three others.

The United States is deploying a U.S. Marine anti-terrorism team to Libya to bolster security after a deadly attack on the American consulate in Benghazi, a U.S. defense official said Wednesday.

"The Marines are sending a FAST (Fleet Anti-terrorism Security Team) team to Libya," the official, who spoke on condition of anonymity, told AFP.

President Barack Obama Wednesday condemned the "outrageous" attack which killed four Americans including the U.S. ambassador in Libya but vowed it would not break America's bond with the liberated nation.

In a somber statement in the White House Rose Garden, Obama paid tribute to Ambassador Chris Stevens and his colleagues, killed when an Islamist mob, angered by reports of a film deemed insulting to Islam, stormed the U.S. consulate in Benghazi.

The Vatican on Wednesday condemned anti-Muslim "provocations" and the resulting "unacceptable violence" after a deadly attack on a U.S. consulate in Libya over a film deemed offensive to Islam.

"The serious consequences of unjustified offense and provocations against the sensibilities of Muslim believers are once again evident," Vatican spokesman Federico Lombardi said in a statement.

The Afghan government on Wednesday banned YouTube from the country for the first time to prevent people from watching an anti-Islam film which sparked a riot in Libya that killed the U.S. ambassador and three other American diplomats.

"Following instructions by the ministry of information and culture, the ministry of communication has ordered all service providers to block YouTube access," communications ministry official Aimal Marjan told AFP.

An Orthodox Israeli rabbi and former cabinet minister on Wednesday condemned as "garbage and slime" a film deemed offensive to Islam that has sparked deadly anti-U.S. protests in Libya and Egypt.

"Although freedom of expression and the right to use satire are sacred democratic principles, these freedoms should not be used as an excuse to publish garbage and slime," Michael Melchior, a long-standing advocate of inter-faith dialogue, wrote in a statement.

Egypt's powerful Muslim Brotherhood on Wednesday called for nationwide protests Friday after a film deemed offensive to Islam sparked a deadly attack in Libya and furious protests in Cairo.

The Brotherhood calls "for peaceful protests on Friday outside all the main mosques in all of Egypt's provinces to denounce offenses to religion and to the Prophet," the Muslim Brotherhood's Secretary General Mahmud Hussein said in a statement.

Security has been stepped up in the area around the US embassy in Cairo, a security official told Agence France Presse, after a film deemed offensive to Islam sparked violence outside the U.S. missions in Egypt and Libya.

"There is an increased security presence in central Cairo, particularly around the American embassy, following the protest yesterday," the official told AFP.

U.S. ambassador to Libya, J. Christopher Stevens, and three officials were killed when a mob attacked the U.S. consulate in the eastern city of Benghazi, the interior ministry said Wednesday.

"The ambassador was killed along with three other officials," said Wanis al-Sharif, the deputy minister of the interior. Stevens' death in Tuesday's attack was confirmed in a tweet by Mustafa Abu Shagur, the deputy prime minister.

An armed mob protesting a film deemed offensive to Islam attacked the U.S. consulate in Benghazi Tuesday killing a U.S. official, hours after angry Islamists stormed Washington's embassy in Cairo.

Libya's deputy interior minister Wanis al-Sharif told Agence France Presse: "One American official was killed and another injured in the hand. The other staff members were evacuated and are safe and sound."