Capitol Police shot dead the driver after he jumped out of the car and lunged at them with a knife, Acting Chief Yogananda Pittman told reporters.
No information was available on the identity of the attacker or his motivation, but Washington Metropolitan Police Chief Robert Contee indicated that a terror link was not suspected at this stage.
“It does not appear to be terrorism-related, but obviously we will continue to investigate,” said Contee.
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.
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.
A helicopter landed on the Capitol grounds and the police were loaded on board to be taken to a hospital.
– Heightened security –
The attack came amid tightened security in Washington after the January 6 insurrection by supporters of then-president Donald Trump.
In that attack, hundreds smashed into the Capitol building yelling threats against politicians and shutting down the legislature.
One Capitol Police officer died as a result of the attack, as well as four others individuals who took part or were nearby.
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 extremist groups like the Proud Boys and Oath Keepers, and 100 more are expected to be charged, according to Justice Department court filings.