A Marine shot dead two fellow service members at a base at Quantico, Virginia, then barricaded himself in a building and apparently killed himself, prompting a brief lockdown of the base, the Marines said on Friday.

The shootings took place late on Thursday in the vicinity of the Marine Corps Base at Quantico's Officer Candidate School, and all three people who died were identified as Marines, Marines spokesman Sergeant Christopher Zahn said.

"An isolated shooting incident has occurred at Officer Candidate School, Quantico," the base said on its Facebook page. "The suspect has been barricaded by law enforcement personnel."

The Facebook message told base residents to remain in their homes with their doors locked, until the lockdown was lifted before dawn on Friday. No other injuries were reported, and Zahn could give no details as to a motive for the shootings.

"The investigation is in the very early stages," he said.

The shootings came days after seven U.S. Marines were killed in a mortar explosion at an Army munitions depot in Nevada during a live-fire training exercise.

In that incident on Monday, a lightweight mortar exploded prematurely in its firing tube, killing the Marines from Camp Lejeune, North Carolina, who had been undergoing mountain warfare training, and wounding eight other service members.

It prompted the Marines to order a blanket suspension of the use of 60mm mortars pending a review.