An incendiary film – and the man killed in the crossfire

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 was set on fire but 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 in the Benghazi Medical Centre at first knew the identity of the ambassador. 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. Some of the protesters scaled the walls of the US embassy in Cairo and burned the American flag while the embassy staff were locked inside protected by US troops. The situation in the Libyan city, however, quickly became much more dangerous with the appearance of firearms and, it is claimed, men seen directing the assault. The consulate was set ablaze and a grenade lobbed in. Local guards had opened fire to try and halt the mob but were forced to flee with the embassy looted.

US officials said last night they believed the attack in Benghazi may have been planned some time ago and the protests over the film used as a cover.

A detachment of 50 US Marines is expected to be sent to guard the embassy in the capital, Tripoli, where embassy staff are being sent, and find those responsible for the attack. Mr Stevens had been on a short visit to Benghazi from Tripoli, at the time of his death. President Obama described him as "a courageous and exemplary representative of the United States who had selflessly served our country and the Libyan people at our mission in Benghazi and supported Libya's transition to democracy. The brave Americans we lost represent the extraordinary service and sacrifices that our civilians make every day around the globe. As we stand united with their families, let us now redouble our own efforts to carry their work forward."

Mohammed Magarief, Libya's interim President, apologised for the "cowardly" killings and pledged that those responsible would be brought to justice. Offering condolences to the families of the four dead he stressed that what happened would not affect the "close relations" with the US.

An Islamist group in Benghazi, Ansar a-Sharia (Supporters of Sharia) initially claimed responsibility for the attack, but later denied that it was involved.

The US administration was braced for possible further attacks at home and in other Muslim countries as news of the film, called Innocence of Muslims, spreads. Afghanistan and Egypt have banned the YouTube excerpt. The film is reported to have been made by a Sam Bacile. An interviewer from the Associated Press described him as a 56-year-old Israeli real-estate developer based in California. But there appears to be no record of him. The Times of Israel described him as a Jewish US citizen who is "familiar" with the Middle East.

Whatever Mr Bacile's provenance, it seems inconceivable that a film that appears so low-budget can have cost $5m (£3m), as he claims. And he has yet to provide evidence that 100 Jewish donors financed the project.

Whatever the cost, Mr Bacile is not apologetic. He told a reporter: "I feel the security system [at embassies] is no good. America should do something to change it," adding that "Islam is a cancer. The movie is a political movie, it is not a religious movie. The US lost a lot of money and a lot of people in wars in Iraq and Afghanistan, but we're fighting with ideas."