White House press secretary Jay Carney is calling the attack on the U.S. Embassy in Ankara, Turkey "an act of terror."

The president's spokesman says it is not yet known who is responsible, but a suicide bombing on the perimeter of an embassy is, by definition, a terrorist act.

A suicide bomber detonated an explosive Friday in front of the embassy in Ankara. He killed himself and a Turkish guard in an attack that Turkish officials blamed on domestic leftists.