The officer killed on duty at the US Capitol earlier today has been identified as William "Billy" Evans, an 18-year US Capitol Police veteran.
"It is with profound sadness that I share the news of the passing of Officer William 'Billy' Evans this afternoon from injuries he sustained following an attack at the North Barricade by a lone assailant," acting US Capitol Police Chief Yogananda Pittman said in the statement.
"Officer Evans had been a member of the United States Capitol Police for 18 years. He began his USCP service on March 7, 2003, and was a member of the Capitol Division's First Responder's Unit. Please keep Officer Evans and his family in your thoughts and prayers."
The suspect has also been identified, as 25-year-old Noah Green. He was shot after exiting the car holding a knife.
"Today, America's heart has been broken by the tragic and heroic death of one of our Capitol Police heroes: Officer William Evans. He is a martyr for our democracy," House Speaker Nancy Pelosi said in the statement.
"Today, once again, these heroes risked their lives to protect our Capitol and our Country, with the same extraordinary selflessness and spirit of service seen on January 6. On behalf of the entire House, we are profoundly grateful," Pelosi added.
US President Joe Biden has also sent his condolences to the family of the slain officer.
"Jill and I were heartbroken to learn of the violent attack at a security checkpoint on the US Capitol grounds, which killed Officer William Evans, of the US Capitol Police, and left a fellow officer fighting for his life." Biden said.
"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."
Flags to be flown at half-mast in honour of slain officer
In the incident, a car rammed a barricade outside the US Capitol on Friday afternoon (US time), killing one officer and injuring another.
The driver of the vehicle was first reported to be in critical condition, but since died.
The crash and shooting happened at a checkpoint near the Capitol as Congress is on recess.
The Washington region remains on edge nearly three months after a mob of armed insurrectionists stormed the Capitol as Congress was voting to certify Joe Biden's presidential win.
Capitol Police said someone "rammed a vehicle into two USCP officers" and a suspect was taken into custody, but had since died.
The law enforcement officials told the AP the suspect was shot and was taken to the hospital in critical condition. One of the officers who was injured was taken by police car to hospital; the other was being transported by emergency medical crews, the officials said.
In a press conference a few minutes later, authorities announced one of the officers had since died.
The US Capitol complex was placed on lockdown after the shooting and staff were told they could not enter or exit buildings. The lockdown has since been lifted.
The incident occurred about 90 metres from the entrance of the building on the Senate side of the Capitol. Fencing that prevented vehicular traffic near that area was recently removed as the Capitol started to open up after the January 6 riots.
The security checkpoint is typically used by senators and staff on weekdays.
Video posted online showed a dark-coloured sedan crashed against a vehicle barrier and a police K9 inspecting the vehicle. Law enforcement and paramedics could be seen caring for at least one unidentified individual.
Speaker Nancy Pelosi has ordered the Capitol flags to be flown at half mast in honour of the officer killed in the attack.
- with AP