The American ambassador to Libya, J. Christopher Stevens, and three officials were killed when a mob attacked the US consulate in the eastern city of Benghazi over a film deemed offensive to Islam, the interior ministry said Wednesday.

"The ambassador was killed along with three other officials," said Wanis al-Sharif, the deputy minister of the interior. Stevens' death in Tuesday's attack was confirmed in a tweet by Mustafa Abu Shagur, the deputy prime minister. Stevens, a career officer with the US foreign service, had been in the country for less than four months after taking up his post in the

capital Tripoli in May.

Fawzi Wanis, who heads the High Security Commission in Benghazi, confirmed that Stevens was at the consulate when it was attacked. Another security source in the city -- cradle of the 2011 uprising that toppled the regime of late dictator Moamer Kadhafi -- speculated that the envoy may have suffocated because of carbon monoxide poisoning.

The ambassador died when an armed mob attacked the US mission, just hours after Islamists also stormed Washington's embassy in the Egyptian capital Cairo. Witnesses said the diplomatic building was ransacked and looted before being set on fire after it was badly damaged by home-made bombs and rocket-propelled grenades.

The film at the centre of the anti-US protests was made by an Israeli-American who describes Islam as a "cancer" and depicts the Prophet Mohammed sleeping with women, the Wall Street Journal reported.

Before confirmation of Stevens' death, US Secretary of State Hillary Clinton announced that a State Department official had been killed in the attack on the consulate, saying: "We are heartbroken by this terrible loss."

Libya's General National Congress (GNC), the country's highest political authority, met late on Tuesday after the consulate attack, a government source said. The country's military chief of staff, Yussef al-Mangush, also cut short a visit to Turkey to return to Tripoli, the same source said.

AFP