The US ambassador to Libya, Christopher Stevens, was among four Americans killed in an attack on the American consulate in Benghazi on Tuesday.
In a statement, confirming the deaths, President Barack Obama said:
"I strongly condemn the outrageous attack on our diplomatic facility in Benghazi, which took the lives of four Americans, including Ambassador Chris Stevens. Right now, the American people have the families of those we lost in our thoughts and prayers. I have directed my Administration to provide all necessary resources to support the security of our personnel in Libya, and to increase security at our diplomatic posts around the globe. While the United States rejects efforts to denigrate the religious beliefs of others, we must all unequivocally oppose the kind of senseless violence that took the lives of these public servants."
More from GlobalPost: US consulates in Benghazi and Cairo attacked over film deemed insulting to Prophet Muhammad
The Wall Street Journal cited Libyan Deputy Prime Minister Mustafa Abushagour as initially confirming Stevens' death:
"I condemn the cowardly act of attacking the US consulate and the killing of Mr. Stevens and the other diplomats," Abushagour said, the WSJ reported.
"This is an attack on America, Libya and free people everywhere."
A Libyan official told Reuters, meantime, that Stevens and the others were being rushed from a consular building as it was stormed by militants angered over a US-made film that they say insults the Prophet Mohammad.
The film, produced by an Israeli film-maker living in California, has sparked angry protests in Egypt and Yemen after excerpts dubbed into Arabic were posted on YouTube.
The film was reportedly being promoted in the US by an anti-Muslim, Egyptian Christian campaigner.
Stevens is usually based in the capital Tripoli but was apparently visiting Benghazi ahead of the planned opening of an American cultural center there.