Update as of 6:55PM

The Navy is investigating the shooting death of a Marine standing guard at Camp Lejeune in North Carolina. A sentry at the camp's main gate reportedly fired his weapon, killing another Marine guard on this evening. 

The base says the incident is not being considered a terrorist act or an active shooter situation.

============

CBS-TV Affiliate WRAL reports a Marine standing guard at the Camp Lejeune in North Carolina main gate shot and killed another Marine this evening.

The military says the incident is not being considered an act of terrorism or an active shooter.

A Camp Lejeune spokesman tells CBS News it's not yet known whether tonight's fatal shooting by a Marine guard of another Marine "was accidental or done on purpose."

The Naval Criminal Investigative Service is investigating the incident. No further details have been released.