Four Americans, including Chris Stevens, the US ambassador to Libya, have been killed in an attack on the American consulate in the eastern Libyan city of Benghazi.
The American envoy is reported to have suffocated in the compound's basement when the consulate building caught fire.
The mission was targeted in a wave of anger over a low-budget, independently financed movie that ridicules the Prophet Muhammad.
The movie, Innocence of Muslims, gained attention after its trailer was dubbed into Arabic and posted on YouTube. The video-sharing website blocked access to it on Wednesday. The trailer depicts Muhammad as a fraud, a womaniser and a madman in an overtly ridiculing way, showing him having sex and calling for massacres.
Stevens was a seasoned diplomat who had served two tours in Libya - once when it was ruled by Muammar Gaddafi and a second during last year's revolution against him.
"What we should get from this event is that the Libyan government should have the humbleness to call the international community for a larger support."
- Karim Mezran, a senior fellow at the Rafik Hariri Center for the Middle East
Stevens was killed along with Sean Smith, the Foreign Service information management officer, and two other Americans after the consulate came under attack.
He was the first US ambassador killed in the line of duty in 30 years.
The violence came on a day when Stevens was visiting Benghazi from Tripoli, the Libyan capital. The US reopened its embassy in the capital only two weeks ago.
Questions have now been raised about why the consulate staff were not better protected from the violence.
Wanees El-Sharaf, Libya's interior minister, said the consulate's security staff were no match for a better armed crowd that would have included Gaddafi loyalists.
The Libyan government has said it will do all within its power to find those responsible for the attacks and bring them to justice.
Earlier, protesters stormed the US embassy compound in the Egyptian capital, Cairo, in protest against the film.
So, what lies behind the latest violence in Libya?
To discuss this Inside Story, with presenter Jane Dutton, is joined by guests: Waheed Burshan, a member of the Libyan National Transitional Council; Omar Ashour, a political analyst and the director of the MA programme in Middle East Studies at Exeter University; and Karim Mezran, a senior fellow at the Rafik Hariri Center for the Middle East with the Atlantic Council.
"The Libyan people are not happy about this. This is embarrassing. Chris Stephens, I know him personally. We were supposed to have lunch in a few days. To me it is disheartening and something very upsetting when I am looking at his emails and expecting to see him in a few days. We are not happy about the situation. We are working extremely hard as Libyans, as people, as leadership to reconstitute ourselves. So, in the meantime we need the support of the international community and we definitely need the support of the United States."
Waheed Burshan, a member of the Libyan National Transitional Council