Christopher Stevens, US ambassador to Libya is among four Americans killed in an attack on the US consulate in the eastern Libyan city of Benghazi, President Barack Obama has confirmed.
Unidentified armed men stormed the grounds on Tuesday night in a protest over a US-produced film that is said to insult the Prophet Muhammad.
They shot at buildings and threw handmade bombs into the compound.
Protesters also attacked the US embassy in Cairo over the film.
In a statement, President Obama condemned the “outrageous attack” on the facility in Benghazi.
“Chris was a courageous and exemplary representative of the United States. Throughout the Libyan revolution, he selflessly served our country and the Libyan people at our mission in Benghazi,” he said.
Mr Obama also ordered a tightening of security at US diplomatic posts around the globe.
The killing was also condemned by the Libyan Deputy Prime Minister Mustafa Abu Shagur.
The US ambassador is believed to have died of suffocation.