A Capitol Police officer was killed and another seriously injured Friday next to Congress headquarters in Washington, DC after a person hit them with a vehicle.
The attacker got out of the car and threatened other officers with a knife.
He was shot and killed when he was taken to hospital.
Four high-ranking officers who have been briefed on the investigation said the suspect is Noah Green, a 25-year-old man from Indiana, who died of his injuries after being shot by police.
The Capitol Police Chief said at a press conference that the attacker
had previous offenses but so far no ties to foreign terrorist groups had been found.
The investigation is in its preliminary phase.
The attack occurred shortly after 1 p.m. at the North Barricade vehicle access point along Independence Avenue.
The Capitol, home to the House of Representatives and the Senate, was closed under a state of alert for more than two hours.
Congress is in recess this week, so many lawmakers had returned to their states.
A car crashed into a barricade in front of the Capitol, injuring two police officers.
A heavy police presence quickly descended on the area.
Multiple ambulances arrived as well as several helicopters.
First responders removed two stretchers from an ambulance and a helicopter landed on the east front of the Capitol.
A perimeter of several streets around has been closed to the public and the press.
A message sent to the Congressional offices read, "Due to an external security threat," "No entry or exit is allowed at this time. You can move inside buildings, but stay away from exterior windows and doors.
Yes is outside, seek shelter. "
Security on Capitol Hill has been beefed up with additional security measures and members of the National Guard since a crowd of Trump supporters stormed the compound during the Jan.6 electoral vote count ahead of a joint session of Congress.
President Joe Biden, who is at Camp David with his family this weekend, has been briefed on the latest details of the situation, White House Press Secretary Jen Psaki said.
The Speaker of the House of Representatives, Nancy Pelosi, ordered that
the flags be flown at half mast
to commemorate the death of the police officer, according to her spokesman Drew Hammill.
Senate Republican Minority Leader Mitch McConnell expressed his concern in a message on Twitter: "I am praying for the Capitol police officers who were attacked. We are still learning what has happened. I appreciate you to all USCP officers and first responders on the scene. "