Pentagon police officer dies in stabbing outside metro entrance, assailant shot dead

A police officer has died after he was stabbed several times in the neck outside the Pentagon on Tuesday, officials familiar with the incident told NBC News.

The officer opened fire on the assailant after the attack began outside the Pentagon metro entrance, according to NBC News. The assailant was shot dead by police, but it's not yet clear which officer killed the assailant.

"I'm incredibly saddened to learn about the passing of a Pentagon police officer, who was killed earlier this morning in a senseless act of violence outside the Pentagon," Sen. Mark Warner, a Virginia Democrat, posted on Twitter Tuesday afternoon.

"My heart goes out to the officer's family and friends, as well as the entire Pentagon Police force," said Warner, who chairs the Senate Intelligence Committee.

The Pentagon was placed on lockdown Tuesday morning after several gunshots were fired near the building, but reopened after more than an hour.

The exact details and sequence of events remains murky. Woodrow Kusse, the police chief of the Pentagon Force Protection Agency, said at a press conference that "several injuries resulted from the incident," but did not confirm the death of the officer.

However, the Fairfax County Police also expressed condolences for the death of a Pentagon police officer.

Kusse said authorities are not actively looking for another suspect: "The incident is over, the scene is secure, and most importantly, there is no continuing threat to our community," he said

The FBI is leading an investigation into the incident as the motivations behind it are still unknown.

"At this time, it would be premature to speculate on motive, and in order to protect the integrity of the investigation we cannot provide additional details at this time," The FBI Washington Field Office said in a statement. "There is no ongoing threat to the public."

The incident occurred on a metro bus platform that is part of the Pentagon Transit Center, only steps away from the Pentagon building in Arlington County, Virginia.

"The Pentagon Metro Station is probably one of the busiest in the transportation system, it is a hub for commuters as well as building occupants," Kusse said at the press conference.

While the lockdown has been lifted, the Pentagon Force Protection Agency tweeted that the public should stay away from the metro rail entrance and bus platform area as it is "still an active crime scene."

Transportation at the Pentagon is now being diverted to Pentagon City, the agency added.

At the time of the shooting, Defense Secretary Lloyd Austin and Gen. Mark Milley, chairman of the Joint Chiefs of Staff, were at the White House for a meeting with President Joe Biden.

The last time a significant incident occurred at the Pentagon Metro Center was in 2010, according to Kusse. 

A gunman opened fire at the Pentagon entrance and wounded two officers with the Pentagon Force Protection Agency in March 2010. The officers, who survived, fatally shot the man soon after.