Protesters storm US Embassy in Yemen following similar attack in Egypt and deadly attack in Libya

Sept. 15, 2012: Egyptian protesters gather around a burning vehicle in downtown Cairo, Egypt, before police cleared the area after days of protests. (AP)

Sept. 15, 2012: Egyptian police detain a man as they clear Tahrir Square in Cairo, Egypt. (AP)

Sept. 13, 2012: Egyptian protesters throw stones at a riot police armored vehicle that was hit by a fire bomb during clashes outside the U.S. embassy in Cairo, Egypt. (AP)

Sept. 13, 2012: An Egyptian protester throws back a tear gas canister toward riot police, unseen, outside the U.S. embassy in Cairo, Egypt. (AP)

Sept. 13, 2012: A riot policeman passes burning vehicles during clashes outside the U.S. embassy in Cairo, Egypt, as part of widespread anger across the Muslim world about a film ridiculing Islam's Prophet Muhammad. (AP)

Sept. 13, 2012: Protesters run as police, unseen, open fire into the air near the U.S. Embassy during a protest about a film ridiculing Islam's Prophet Muhammad, in Sanaa, Yemen. (AP)

Sept. 13, 2012: Damaged vehicles are seen as protesters gather outside the U.S. embassy in Sanaa, Yemen. (AP)

Sept. 13, 2012: Protesters gather outside the U.S. embassy in Sanaa, Yemen. (Reuters)

Sept. 13, 2012: Yemeni protestors break a door of the U.S. Embassy during a protest about a film ridiculing Islam's Prophet Muhammad, in Sanaa, Yemen. (AP)

Sept. 13, 2012: A Yemeni protestor, left, holds a white flag with Islamic inscription in Arabic that reads, "No God but Allah, and Mohammed is his prophet," in front of the U.S. embassy during a protest about a film ridiculing Islam's Prophet Muhammad, in Sanaa, Yemen. (AP)

Sept. 13, 2012: Yemeni protestors climb the gate of the U.S. Embassy during a protest about a film ridiculing Islam's Prophet Muhammad, in Sanaa, Yemen. (AP)

Sept. 13, 2012: A Yemeni protester, center, destroys an American flag pulled down as other hold a banner in Arabic that reads, "any one but you God's prophet" at the U.S. Embassy compound during a protest about a film ridiculing Islam's Prophet Muhammad, in Sanaa, Yemen.

Sept. 13, 2012: Yemenis protest in front of the U.S. Embassy about a film ridiculing Islam's Prophet Muhammad, in Sanaa, Yemen. (AP)

Sept. 13, 2012: Yemeni protesters break a window of the U.S. Embassy during a protest about a film ridiculing Islam's Prophet Muhammad, in Sanaa, Yemen. (AP)

Sept. 12, 2012: Protesters march during a demonstration to denounce terror attacks and to show support for Yemen's President Abd-Rabbu Mansour Hadi's decision to replace security officials, in Sanaa, Yemen. (Reuters)

This still image made from a Reuters video shows protesters storming the U.S. Embassy in Yemen. (REUTERS)

U.S. Ambassador Chris Stevens, right, and three other Americans have been killed in an attack on the U.S. consulate in the eastern city of Benghazi, left, by protesters angry over a film that ridiculed Islam's Prophet Muhammad. (AP/Reuters)

After U.S. consulate in Benghazi began taking fire in attack, personnel effectively lost track of U.S. Ambassador to Libya Christopher Stevens -- shown being dragged by Libyans -- and did not recover his body until hours later. It was not known whether Stevens was alive when photo was taken. (AFP)

Sept. 11, 2012: Damage at the U.S. Consulate in Benghazi is seen during a protest by an armed group said to have been protesting a film being produced in the United States. (REUTERS)

Sept. 11, 2012: The U.S. Consulate in Benghazi is seen in flames during a protest. (REUTERS)

Sept. 11, 2012: A protester reacts as the U.S. Consulate in Benghazi is seen in flames during a protest by an armed group said to have been protesting a film being produced in the United States. (REUTERS)

Sept. 11, 2012: Egyptian protesters climb the walls of the U.S. embassy while others chant anti U.S. slogans during a protest in Cairo, Egypt. (AP)

Sept. 11, 2012: Egyptian protesters wearing Guy Fawkes masks pose for a photo graffiti on a wall of the U.S. embassy during a protest in Cairo, Egypt. (AP)

Sept. 11, 2012: Egyptian protesters climb the walls of the U.S. embassy with Arabic graffiti that reads "any one but you God's prophet" during protests in Cairo, Egypt. (AP)

Sept. 11, 2012: Egyptian protesters climb the walls of the U.S. embassy with Arabic graffiti that reads "any one but you God's prophet" during a protest in Cairo, Egypt. (AP)

Sept. 11, 2012: Protesters destroy an American flag pulled down from the U.S. embassy in Cairo, Egypt. (AP)

Sept. 11, 2012: Egyptian protesters chant anti U.S. slogans in front of the U.S. embassy in Cairo, Egypt. (AP)

Sept. 11, 2012: Protesters chant slogans amid orange smoke outside the U.S. embassy in Cairo, Egypt. (AP)

Sept. 11, 2012: Protesters chant slogans outside the U.S. embassy in Cairo, Egypt. (AP)

Egyptian protesters climb the walls of the U.S. embassy during protests in Cairo, Egypt, Tuesday, Sept. 11, 2012. Egyptian protesters, largely ultra conservative Islamists, have climbed the walls of the U.S. embassy in Cairo, went into the courtyard and brought down the flag, replacing it with a black flag with Islamic inscription, in protest of a film deemed offensive of Islam. (AP Photo/Nasser Nasser) (AP2012)

Sept. 11, 2012: Protesters chant slogans amid orange smoke outside the U.S. embassy in Cairo, Egypt. (AP)