Four Americans dead in attack in Afghanistan

An explosion at Bagram Airfield in Afghanistan killed four Americans early this morning, the U.S. military said. U.S. Secretary of Defense Ash Carter said in a statement that two U.S. servicemen and two American contractors died in the blast, and another 16 U.S. service members and one Polish soldier were wounded. The Taliban claimed responsibility for the attack, which they said a suicide bomber carried out inside the base. The Taliban regularly fire rockets at the U.S. base from outside its perimeter.

The Associated Press contributed to this report.