A Yemeni soldier inspects a car at a checkpoint on a street leading to the U.S. embassy in Sanaa, Yemen, Sunday, Aug. 4, 2013. Security forces close access roads, put up extra blast walls and beef up patrols near some of the 21 U.S. diplomatic missions in the Muslim world that Washington ordered closed for the weekend over a "significant threat'' of an al Qaeda attack. (AP Photo/Hani Mohammed)

Photo by: Hani Mohammed

A Yemeni soldier inspects a car at a checkpoint on a street leading to the U.S. embassy in Sanaa, Yemen, Sunday, Aug. 4, 2013. Security forces close access roads, put up extra blast walls and beef up patrols near some of the 21 U.S. diplomatic missions in the Muslim world that Washington ordered closed for the weekend over a "significant threat'' of an al Qaeda attack. (AP Photo/Hani Mohammed)