The US ambassador to Libya and three members of his staff were killed in an attack by an armed mob which stormed the country's consulate in Benghazi in a furious protest over an American film mocking the Prophet Mohammed.
The deaths, in the worst breach of security for an American mission for decades, led to President Barack Obama ordering the immediate upgrading of protection for the country's diplomats in potentially vulnerable foreign posts.
Chris Stevens and his team had tried to flee after the consulate had been set on fire, when their car was hit by a rocket-propelled grenade. Two Marines and a Press officer, Sean Smith, a father-of-two, were shot dead by gunmen who had surrounded the vehicles.
The 52-year-old ambassador was dragged out by a group of Libyans, according to one account, and taken to a hospital.
Dr Ziad Abu Ziad said no one at first knew the identity of the ambassador, the only Western person to be brought into the Benghazi Medical Centre. Mr Stevens had no physical injuries said the doctor, but died from smoke inhalation despite efforts for more than 90 minutes to revive him.
He was the first US head of mission to be killed in his post since Adolph Dubs, who was murdered after being kidnapped in Afghanistan in 1979.
The outpouring of rage in Benghazi had followed violent demonstrations in Cairo in reaction to the video, which had been dubbed into Arabic and posted on YouTube.