Two officers were injured near the US Capitol when a vehicle rammed into them, police said, less than three months after the Congress came under attack from an extreme-right mob.
The Capitol was on lockdown with National Guard troops mobilized after shots were reportedly fired in the incident.
NBC News reported that the driver of the car was shot after attempting to leave it carrying a knife.
“A suspect is in custody. Both officers are injured. All three have been transported to the hospital,” the US Capitol Police said on Twitter.
Shortly after that, both NBC and ABC News reported that the attacker was dead.
Television footage showed a blue sedan that had 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.
A helicopter landed on the Capitol grounds and the police were loaded on board to be taken to a hospital.
No information was immediately available on the identity or condition of the driver.
The incident came amid tightened security in Washington after the January 6 insurrection by supporters of then-president Donald Trump.
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.
Since then security officials have said there is an ongoing threat from extreme right groups and Trump supporters.
More than 300 people have been charged in the January attack, including members of armed extremists groups like the Proud Boys and Oath Keepers, and 100 more are expected to be charged, according to Justice Department court filings.
In recent weeks some security has been loosened, with the number of armed National Guard troops at the Capitol reduced and a security fence that created a broad perimeter around the Capitol complex removed.
CBS News reported that security officials had already warned congressional staffers of a threat before the car ramming.
Text messages sent to staffers inside told them to avoid windows and said no one could enter or leave the building.
“If you are outside, seek cover,” the messages said.
But the danger on Friday was limited as Congress was in recess for the Easter holiday and relatively few people were in the building.
Security officials, including the Capitol Police and National Guard, were faulted for reacting slowly to the crowds who stormed the Capitol on January 6.
Several hundred rioters broke down doors and windows and poured into the halls of the legislature, some calling for physical attacks on various members of Congress and on then-vice president Mike Pence, who was there to preside over a session to formally declare Joe Biden the winner of the election.
While the incident remains under investigation, some have alleged that Trump and supporters encouraged the attack and that Trump officials held back on deploying addition law enforcement and troops to fight back the attackers.
Since then several thousand National Guardsmen and women have remained deployed to the US capital city due to ongoing security concerns.