Three Marines were relieved of their duties after the incident . The four Marines were working on range area known as Zulu Black used for live-fire drills . But the deaths did n't occur under such live fire , a military source says . It 's possible that unexploded ordnance suddenly detonated , the source says . A U.S. official tells CNN it is unclear if any of those killed are American or Afghan troops.
The four Marines were working on range area known as Zulu Black used for live-fire drills . But the deaths did n't occur under such live fire , a military source says . It 's possible that unexploded ordnance suddenly detonated , the source says . A U.S. official tells CNN it is unclear if any of those killed are American or Afghan troops.