ANKARA, Turkey (February 1, 2013)—A suicide bomber detonated an explosive device Friday at the entrance of the U.S. Embassy in the Turkish capital, killing himself and a Turkish security guard.

The bomb appeared to have exploded inside the security checkpoint at the entrance of the embassy.

Private NTV television says two security guards at the entrance were killed.

White House press secretary Jay Carney called the attack "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.