The United States Capitol was locked down on Friday due to an "exterior security threat" after a car rammed into a barrier on the Senate side of the complex. One officer died and another was injured, according to United States Capitol Police (USCP), who said the suspect was killed by police after he exited his navy sedan and attacked them with a knife.
Fox News was told by security officials that the incident was believed to be a "lone wolf" attack.
The suspect, Noah Green, 25, was from Indiana and also had ties to Virginia.
Metropolitan Police Department Acting Chief Robert Contee said in a briefing the attack did not appear to be terrorism-related and the man had no known connection to a member of Congress. The suspect was not known to police.
Two law enforcement sources told Fox News that during the encounter, the suspect stabbed one of the officers.
The officer who died was identified as William "Billy" Evans. He had been a member of USCP for 18 years.
The other USCP officer who was struck by the car is in stable and non-threatening condition, Capitol Police announced.
Acting USCP Chief Yogananda Pittman said the suspect had exited the car, knife in hand, and "lunged toward" Capitol Police.
"Due to an exterior security threat, no entry or exit is permitted at this time in any building in the Capitol complex," a voice announcement throughout the complex sounded earlier Friday afternoon.
"You may move around the buildings but stay away from exterior windows and doors," it also said.
The lockdown has since been lifted.
USCP said the suspect and two injured officers were taken to the hospital, before the suspect and one officer succumbed to injuries.
"This has been an extremely difficult time for US Capitol Police after the events of January 6, and now the events that have occurred here today. So, I ask that you keep our US Capitol Police family in your thoughts and prayers," Pittman said. One police officer died as a result of the Jan. 6 Capitol riot, and two subsequently died of suicide after the attack.
President Biden, who is at Camp David weighed in on the attack.
"Jill and I were heartbroken to learn of the violent attack at a security checkpoint on the U.S. Capitol grounds, which killed Officer William Evans of the U.S. Capitol Police, and left a fellow officer fighting for his life. We send our heartfelt condolences to Officer Evans’ family, and everyone grieving his loss. We know what a difficult time this has been for the Capitol, everyone who works there, and those who protect it," the president said in a statement.
"I want to express the nation’s gratitude to the Capitol Police, the National Guard Immediate Response Force, and others who quickly responded to this attack," Biden said. He said he'd receive ongoing updates from his homeland security advisor and had ordered the flags at the White House to be flown at half-staff.
House Speaker Nancy Pelosi, D-Calif., also ordered all flags at the Capitol to be flown at half-staff to honor the officer who died in the incident.
The D. C. National Guard also deployed an Immediate Response Force to the scene.
The FBI Washington Field Office tweeted that it is supporting the Capitol Police in responding to the incident.
"Praying for the United States Capitol Police officers who were attacked at the Capitol," Senate Minority Leader Mitch McConnell, R-Ky., tweeted. "We are still learning what’s taken place. Grateful to all the USCP and first responders who are on the scene."
The entry point where the scene unfolded is directly where senators and aides enter the Capitol each day. The incident occurred at the North barricade vehicle access along Constitution Avenue. Capitol Police had originally reported Independence Avenue before issuing a correction.
Constitution Avenue was closed off until two weeks ago when they reduced the size of the outer perimeter. The National Guard is still stationed there.
There was a car visibly smashed into a barrier outside of the Capitol.
Video showed a helicopter landing on the East Front of the Capitol to respond to the scene.
White House Press Secretary Jen Psaki said Friday that she did not have an update about any change in security posture at the White House. She was not aware of the episode as she gave her daily briefing.
The incident comes as the Capitol has been fortified for months following the Jan. 6 attack on the building by a pro-Trump mob, after which law enforcement erected a fence for hundreds of yards beyond the buildings of the Capitol complex.
In recent weeks, the perimeter around the Capitol was reduced as the security posture around the complex was relaxed.
Fox News' Hillary Vaughn, Christopher Wallace and Chad Pergram contributed to this report.