US ambassador to Libya J. Christopher Stevens and three of his staff were killed as an armed mob apparently incensed over a US-made film critical of Islam attacked the American consulate in Benghazi.
Confirming the four deaths in the attack in the eastern city Tuesday night, President Barack Obama Wednesday said he strongly condemned the killings and had ordered increased security at American diplomatic posts around the world.
Obama praised Stevens, who had also served as an envoy to the Libyan movement, that overthrew Muammar Gaddafi last year, based in the rebel capital of Benghazi for having "supporting Libya's transition to democracy".
A speaker of Arabic and French, he was among the first American diplomats sent to Libya in 2007 when the US resumed ties with the Gaddafi regime. He was appointed ambassador in May.
The offending film ridiculing Prophet Mohammed also prompted a similar attack on the US embassy in Cairo, according to various media reports.
US Secretary of State Hillary Clinton condemned the attack "in the strongest terms". She said she had called Libyan President Mohamed Yusuf al-Magariaf "to coordinate additional support to protect Americans in Libya".
Clinton identified a second victim as Sean Smith, a Foreign Service information management officer who was a 10-year veteran of the State Department, a husband and a father of two. The two other victims have not been named.
Libya's Deputy Interior Minister Wanis al-Sharif said an "angry crowd" marched on the US compound Tuesday, furious about an American-produced online film considered offensive to Muslims, CNN reported.
Consulate security staff opened fire after they heard gunfire outside the mission, al-Sharif said.
"This led to more anger and this is when the consulate was stormed," he said, suggesting that people loyal to Gaddafi were aiming to create chaos among the protesters.
"Criminals managed to get in and they burned and ransacked the consulate," he said.
The US mission is very badly damaged and was being looted Wednesday, CNN said citing a contractor working at the mission. He said he saw the bodies of all four Americans on the street Wednesday morning.
The last time an American ambassador was killed by terrorists was in 1979, when the envoy to Afghanistan, Adolph Dubs, was kidnapped and killed during an attempt to rescue him, according to State Department records, CNN said.
"I do condemn the cowardly act of attacking the US consulate and the killing of Mr. Stevens and the other diplomats," Libya's Deputy Prime Minister Mustafa Abushagur said on his Twitter account as cited by CBS News.