WASHINGTON (September 12, 2012)--President Barack Obama Wednesday condemned in the "strongest possible terms" the attack on the U.S. consulate in Libya that killed four Americans, including the American ambassador.

Mr. Obama said the U.S. will work with the Libyan government to bring the perpetrators of the attack to justice and said "no acts of terror" will shake America's resolve.

Mr. Obama said the U.S. rejects any efforts to denigrate the religious beliefs of others, but says there is "absolutely no justification" for violent attacks.

U.S. Ambassador Chris Stevens was killed, Libyan officials say, when he and embassy aides went to the U.S. consulate in Benghazi, which was under attack by protesters angry over a film that ridicules Islam's Prophet Muhammad.

Mr. Obama was notified that Stevens was unaccounted for Tuesday night and was told of his death Wednesday morning.

The U.S. consulate in the Libyan city of Benghazi was burned out and trashed, in the aftermath of the attack.

Libyans were wandering freely around the burned-out building, taking photos of rooms where furniture is covered in soot and overturned.

The consulate is a one-story villa in a large garden, located in an upscale neighborhood.

The attack was carried out by a crowd of hundreds, many of them firing machine-guns and rocket-propelled grenades.

A Libyan doctor who treated Stevens said the ambassador died of severe asphyxiation, evidently from smoke.

In the chaos surrounding the attack, Libyans took Stevens to a hospital with no other Americans.

A doctor there said no one at the facility knew who he was.

Secretary of State Hillary Rodham Clinton said Stevens and three other Americans who were killed in the attack were "committed to helping the Libyan people reach for a better future."

Stevens was a career diplomat who was confirmed as ambassador to Libya by the Senate earlier this year.

He had already served two tours in Libya, and had run the office in Benghazi during the revolt against Moammar Gadhafi.

Clinton said Stevens had a "passion for service, for diplomacy and for the Libyan people."

She said he was dedicated to "advancing closer ties with the people of the Middle East and North Africa" and said Stevens "risked his own life to lend the Libyan people a helping hand to build the foundation for a new, free nation"

Stevens joined the Foreign Service in 1991 and spent time in Saudi Arabia, Egypt, Syria and Israel.

About 50 U.S. Marines were sent to Libya to reinforce security at U.S. diplomatic facilities in the aftermath the attack.

The Marines are members of an elite group known as a Fleet Antiterrorism Security Team, whose role is to respond on short notice to terrorism threats and to reinforce security at U.S. embassies.

They operate worldwide.

The officials who disclosed the plan to send the Marines spoke on condition of anonymity because they were not authorized to speak publicly.