WASHINGTON (CNN) -- A Marine shot and killed two of his fellow service members at a Virginia base on Thursday night and then apparently killed himself, base officials said.
The incident took place at Marine Corps Base Quantico. The shooter gunned down a man and a woman, the spokesmen said. All are Marines -- permanent personnel assigned to the officer candidate school.
Authorities did not disclose a motive and were investigating the incident. The identities of the victims were not immediately disclosed as authorities work to notify next of kin.
"It's been a long night," Col David Maxwell, the base commander, said Friday.
The incident shocked the military community. Pentagon Press Secretary George Little said in a Twitter message that he was "saddened to hear of loss of life" at Quantico. It comes as the corps grieves over another tragedy, the deaths of seven U.S. Marines in a training exercise in Nevada on Monday.
As the incident unfolded, earlier Marine accounts said the notification of a shooting came late Thursday when authorities found one dead victim.
Using a public address system, police announced a lockdown at Marine Corps Base Quantico and surrounded the building where the suspect was believed to be barricaded. They ordered everyone to stay in their homes, doors locked, they said.
Authorities from the base and Prince William County, Virginia, surrounded the shooter, who was in a barracks not far from where the first shooting occurred.
Law enforcement officials entered the room two hours later and discovered the shooter dead, apparently of a self-inflicted wound. The female victim was in the room with him, fatally shot.
The lockdown ended early Friday, a few hours after it started.
As dawn rose over the base, Maxwell told reporters that there were no barricades or a standoff but did not elaborate. The incident was confined to a single barracks at the candidate school.
He said "quick" police reaction helped resolve the situation, first reported at 10:30 p.m. via an emergency call. Soon, security was heightened and a mass notification was issued throughout the base. Base restrictions were lifted a few hours later.
Others in the officer candidate school were "accounted for and safe."
"As we take care of our Marines and their families that are dealing with this tragedy, I'd also ask for the support of our neighbors, the community, and their thoughts and prayers as well for our Marines who have lost their comrades-in-arms," Maxwell said
This article was written by CNN's Alison Harding and Shannon Travis. CNN's Jake Carpenter contributed to this report. TM & © 2012 Cable News Network, Inc., a Time Warner Company. All rights reserved.