WASHINGTON — A woman driving a black Lexus tried to ram through a White House barricade Thursday, then led police on a chase that ended in gunfire outside the Capitol, witnesses and officials said.

Tourists watched the shooting unfold on Constitution Avenue outside the Capitol as lawmakers inside debated how to end a government shutdown. Police quickly locked down the entire complex for about an hour, and both houses of Congress went into recess.

The pursuit began when a car tried to ram a security barricade blocking the stretch of Pennsylvania Avenue in front of the White House, according to a law enforcement official who was not authorized to discuss the case by name and insisted on anonymity.

Witnesses said at least 20 police cars chased the Lexus toward Capitol Hill, where the car crashed outside the Capitol.

Tourist Edmund Ofori-Attah said he walked toward the scene, curious about what was going on.

“Then I heard the gunfire” and hit the ground, he said.

Senate Sergeant at Arms Terrance Gainer said a woman was driving the car and had a child with her. Ofori-Attah said the child appeared to be about 2 to 3 years old.

Gainer said the child was taken to a hospital.

Capitol Police Chief Kim Dine said the driver was in custody. He did not disclose her condition.

A police officer was injured in the traffic accident but Gainer said the injuries were not life threatening.

“We heard three, four, five pops,” said Sen. Bob Casey, D-Pa., who was walking from the Capitol to an office building across the street. Police ordered Casey and nearby tourists to crouch behind a car for protection, then hustled everyone into the Capitol.

“There were multiple shots fired and the air was filled with gunpowder,” said Berin Szoka, whose office at a technology think tank overlooks the shooting scene.

The shooting comes two weeks after a mentally disturbed employee terrorized the Navy Yard with a shotgun, leaving 13 people dead including the gunman.

Before the disruption, lawmakers had been trying to find common ground to end a government shutdown. The House had just finished approving legislation aimed at partly lifting the government shutdown by paying National Guard and Reserve members.

People standing outside the Supreme Court across the street from Congress were hurried into the court building by authorities.

The White House also was briefly locked down after the incident at Capitol Hill and the stretch of Pennsylvania Avenue in front of the compound was closed to pedestrians. Secret Service said the procedures were precautionary.