Authorities have reported that an unnamed man has shot and killed a U.S. Navy sailor at Naval Station Norfolk in Virginia, The Sailor was on the destroyer USS Mahan when he was shot by the man, who was then killed by base security forces or police.

Terri Davis says the shooting happened around 11:20 p.m. Monday aboard the USS Mahan, a destroyer. Davis would not describe the circumstances of the shooting but said the scene is secure.

Davis says the two killed were both males but she didn’t have any other information on them. She could not say if the civilian had permission to be aboard the ship or not. No other injuries were reported.

The base — the largest naval installation in the world — was briefly put on lockdown after the shooting as a precaution, but it has since been lifted. Security at the facility’s gates were to remain at the usual level Tuesday morning. Sailors on board the USS Mahan have been cleared to return to work.-AP