Reuters is reporting that four Americans were killed in the attack on the United States consulate in Benghazi on Tuesday, and that one was the U.S. Ambassador to Libya J. Christopher Stevens. The State Department has not confirmed or denied this latest report, according to France24 news. A Libyan official said that Stevens and the other three staff members were killed when someone fired rockets at them in their car, but other reports say he died from asphyxiation from smoke. Two of the others killed were reportedly Marines providing security at the embassy.

Stevens is a lifelong member of the foreign service, working for the U.S. government in Jerusalem, Damascus, Cairo, and Riyadh since joining in 1991. He was the lead representative for the United States during the Libyan revolution last year, working on the ground with the opposition council that helped to topple Muammar Qaddafi. He was officially appointed to the post of ambassador in May of this year.

A mob of angry protesters stormed the consulate building on Tuesday following the spread of an online video that the reportedly insults the Prophet Muhammad. Libyan security forces were overrun and the building was burned and looted. A similar protest took place at the U.S. embassy in Egypt. Most of the rioters have not even seen the video, but outrage was stirred up by Salafi extremists who accused the U.S. of being behind the video.

Many Libyans, as well as other Arabs and Muslims across the region are condemning the incidents as an attack on their revolutions.

CNN says that a foreign contractor who worked at the embassy and knew the ambassador confirmed to them that he identified Stevens' body on the street. Several pictures have circulated on the internet showing a man who appears to be the ambassador being carried away, but it is not confirmed that the pictures are of Stevens. Nor is it known if the other people are protesters or rescuers trying to help. You can see the photo on here and here, but be warned that the pictures may be disturbing.

According to the State Department website, there have only been five other U.S. ambassadors killed while on duty. The last was Adolph Dubs who was killed in Afghanistan in 1979, following the Soviet-led coup.

Update: 7:23 a.m.: President Obama has issued a statement about the death of Ambassador Stevens:

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. They exemplified America's commitment to freedom, justice, and partnership with nations and people around the globe, and stand in stark contrast to those who callously took their lives. 

You can read the whole statement here.

7:42 a.m.: ABC News' Jake Tapper reports that the State Department has identified one of the other Americans killed in the attack as Sean Smith, a Foreign Service Information Management Officer.

7:54 a.m.: Libya's Prime Minister just held a press conference, live on Al Jazzera TV. He publicly apologized to the United States for the attack, but also suggested that the remnants of the old Qaddafi regime may have been responsible.

9:22 a.m.: President Obama will speak in the Rose Garden at 10:35. Mitt Romney is also expected to address the matter when he speaks in Jacksonville, Florida, later today.

9:28 a.m.: The Muslim Brotherhood in Egypt, the leading political party in that country, has also condemned the Libya attack.

9:34 a.m.: CNN reports that additional U.S. Marines are being sent to Benghazi to beef up security in the area.