The U.S. ambassador to Libya and three other embassy staff have been killed in an attack on the U.S. consulate in the eastern Libyan city of Benghazi, al Jazeera television reported, citing local officials.
Ambassador Chris Stevens died of smoke inhalation on Tuesday after the facility was set on fire by an armed mob angry over a U.S.-produced film that is said to be insulting to Islam's Prophet Muhammad.
The U.S. State Department has so far confirmed the death of just one official, but has not named him.
Stevens had been paying a brief visit to the city, which was the stronghold of resistance against the rule of late former leader Muammar Gaddafi, who was killed by rebel militia in October last year.
Two U.S. security personnel and a consulate employee were also killed in the attack, Libyan officials said.
A further two employees were injured.
Rocket-propelled grenades were fired at the U.S. compound, a spokesman for Libya's Supreme Security Committee said.
Spokesman Abdel-Monem al-Hurr said there were also "fierce clashes" between the Libyan forces and the attackers.
Protesters also attacked the U.S. consulate in the Egyptian capital Cairo on Tuesday.
The incidents occurred on the 11th anniversary of the 9/11 attacks in the United States.
The video, Innocence of Muslims, has been actively promoted by a Florida pastor, Terry Jones, who gained notoriety for threatening to burn and then burning a Koran that set off riots in Afghanistan in 2010 and 2011, the New York Times reported.
Jones has proclaimed September 11 to be “International Judge Muhammad Day.”
A statement on his website said the video “is an American production, not designed to attack Muslims but to show the destructive ideology of Islam. The movie further reveals in a satirical fashion the life of Muhammad.”
Sam Bacile, a real estate developer in California who has called Islam a “cancer,” said he financed production of the video with $5 million provided by Jewish donors, the Wall Street Journal said.