A man was fatally shot Monday night after he confronted security personnel and shot and killed a U.S. sailor aboard a Navy destroyer at Norfolk Naval Station in Virginia, officials said.

The naval station was under a 45-minute security lockdown after the incident, but it had returned to normal operations by Tuesday morning as officials worked to figure out the circumstances that led to the shooting, said Beth Baker, a spokeswoman for the base.

The incident occurred about 11:20 p.m. aboard the USS Mahan, a destroyer that is docked at the Norfolk station’s Pier 1.

The man approached the destroyer’s deck and was confronted by ship security personnel. Officials said that a struggle ensued and that the attacker was “able to disarm” a petty officer on the ship. The man then used the weapon to fatally shoot a sailor responding to the incident.

Naval security forces then killed the attacker, officials said. The man did not have his own weapon, the Navy said.

In this May 26, 2004, file photo, the USS Mahan, a guided-missile destroyer, moves up the Hudson River in New York. (Ed Bailey/AP)

The names and ages of those involved were not released, pending notification of relatives. Both men were pronounced dead at the scene. No one else was injured.

Baker said the attacker was a civilian who “did have authorization to be on the naval station.” She said it was “unclear if he had authorization to be on the destroyer.”

The base is one of the largest naval installations in the world and covers more than 6,000 acres, according to the Associated Press. It is the home port for 64 ships and a Navy hospital ship. About 46,000 military members and 21,000 civilian employees and contractors are assigned there.

The shooting comes about a month after the Navy held anti-terrorism and force-protection exercises around the world, including an active-shooter drill at the Norfolk base, according to the Associated Press.

It also follows a September mass shooting at the Washington Navy Yard, in which Aaron Alexis gunned down 12 Navy civilian personnel and contractors before being fatally shot.

Julie Zauzmer contributed to this report.