A video attacking the Prophet Mohammed has sparked an attack on US embassy in Libya in which the American ambassador was killed.

US Ambassador Christopher Stevens was killed together with three other consulate workers after a pro-Islamist riot broke out in the city of Benghazi yesterday evening. Mr Stevens, who served as deputy principal officer and political section chief at the consulate in Jerusalem during his career in foreign service, was 52.

The 14-minute YouTube clip depicts the Muslim prophet as a psychotic womaniser.

According to the Wall Street Journal, AP and Reuters, a man claiming to be an Israeli named Sam Bacile said that he received $5 million from 100 Jewish donors to make the film. It soon emerged however that the man behind the film was in fact a Coptic Christian living in California. 

Wanis al-Sharef, an Interior Ministry official in Benghazi, said that Libyan security did little to stop the growing crowd.

The riot, which took place on the 11th anniversary of 9/11 attacks, began after protesters challenged the anti-Islam film attacking the Prophet Mohammed.

Protests also broke out in Cairo yesterday, where the US embassy was attacked, the US flag was replaced with an Islamic banner and a group of women in Cairo shouted, "Worshippers of the Cross, leave the Prophet Mohammed alone," according to The Times of Israel.