FORT CAMPBELL, Ky. -

A Fort Campbell-based soldier from Georgia was among five killed in Afghanistan last week.

The Department of Defense announced Saturday that 28-year-old Staff Sgt. Jason A. McDonald of Butler, Ga., was killed June 9 while engaged in a combat operation in Gaza Village, Afghanistan.

Media reports said the soldiers were parts of U.S. Special Forces working with the Afghan military to conduct sweeps of polling places ahead of run-offs for the Afghanistan presidential election. Stars and Stripes reported the Americans called in an airstrike from a B-1 Stealth Bomber amid the fight.

Also killed were Staff Sgt. Scott R. Studenmund, 24, of Pasadena, California; Spc. Justin R. Helton, 25, of Beaver, Ohio; Cpl. Justin R. Clouse, 22, of Sprague, Washington; and Pvt. 2nd Class Aaron S. Toppen, 19, of Mokena, Illinois.

It is not yet know why the bomb was dropped in the location of the American soldiers.

The Pentagon only said the five died due to wounds suffered during combat operations, but a report from the International Security Assistance Force said the deaths were due to fratricide, the military term for casualties caused by friendly fire.

The Pentagon said the incident is under investigation.

McDonald was assigned to the 1st Battalion, 5th Special Forces Group at Fort Campbell, located on the Kentucky-Tennessee state lines.