Capitol Police shot dead the driver after he jumped out of the auto and lunged at them with a knife, Acting Chief Yogananda Pittman told reporters. "All three have been transported to the hospital", their statement said.
Just months after the January 6 riot, Capitol Hill has once again come under emergency lockdown as breaking reports of the shooting of two Capitol Police officers surfaced on social media.
It occurred about 100 yards (91 meters) from the entrance of the building on the Senate side of the Capitol.
Update: Law enforcement sources have told ABC News that the suspect is dead.
But Congress is now in recess, meaning the majority of politicians are not at the Capitol complex today.
"I just ask that the public continue to keep U.S. Capitol Police and their families in your prayers", Pittman said.
The FBI's Washington, D.C., field office said it had "responded to an incident at the U.S. Capitol" and is providing support to Capitol Police.
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The officer was identified by Pittman later Friday as Officer William "Billy" Evans, an 18-year veteran of the force and a member of its "First Responders Unit".
Five people, including a Capitol Police officer, died in the assault inspired by Trump's groundless claims that he had lost the November presidential election due to massive fraud. At the end of last month, Capitol police announced that all fencing around the outer perimeter of the complex had been removed. Pittman said one of the officers was killed and the other was injured.
The security checkpoint is typically used by senators and staff on weekdays.
Authorities have begun only in the past couple of weeks to remove the outer ring of high, razor-wire-topped fencing erected around the sprawling Capitol complex after the January 6 rampage.
Television footage showed a blue sedan crashed into a security barrier on one of the streets leading to Congress, as what appeared to be the injured officers were loaded onto gurneys and into ambulances. Law enforcement and paramedics could be seen caring for at least one unidentified individual.
President Joe Biden left Washington earlier in the day for Camp David, the presidential retreat in Maryland.
National Guard troops were mobilized and staff at the huge Capitol complex ordered to stay away from windows and seek cover after alerts went out over the incident. As customary, he was traveling with a member of the National Security Council Staff who was expected to brief him on the incident.