No other injuries were reported, and the base was briefly on lockdown, according to the Navy. David would not describe any other circumstances of the shooting but said the scene was secure.
The Navy will release both men's names once their families are notified, Davis said.
Operations had returned to normal at the base, with counselors available, the Navy said in a news release. But most enlisted sailors on the Mahan docked at the first of 13 main piers were not to report to duty Tuesday. Base traffic was typical Tuesday morning.
The shooting on the Mahan comes about a month after the Navy held anti-terrorism and force protection exercises on bases around the US, including an active-shooter drill at the Norfolk station.
To get on the base, civilians must be escorted or have identification that allows them to be there. Authorized civilians can include Department of Defense employees, contractors and military family members. Davis would not elaborate on how the suspect was authorized to get on base.
The shooting comes months after a September incident at the Washington Navy Yard, in which a gunman identified as a contractor and former Navy reservist killed 12 civilian workers before being shot to death.
The Mahan, commissioned in 1998, has a crew of nearly 300. In September, it returned to Norfolk after a deployment of more than eight months that included being positioned in the eastern Mediterranean Sea for a potential strike against Syria. AP