WASHINGTON (Sputnik) — Earlier in the day, NATO’s Resolute Support mission announced that the explosion occurred at the air base. around 5:30 a.m. local time (01:00 GMT).
"I am deeply saddened to learn that an explosion early this morning at Bagram Airfield in Afghanistan has resulted in U.S. casualties. An apparent suicide bomber has taken the lives of two U.S. service members and two U.S. contractors working on the base. The explosion wounded 16 other U.S. service members and one Polish soldier participating in our NATO mission," Carter said in a statement.
The defense secretary vowed to "investigate this tragedy to determine any steps we can take to improve" the protection of the US forces.
The United States has been carrying out a counter-terrorist operation in Afghanistan since 2001.