WASHINGTON — Law enforcement authorities were investigating why a Connecticut woman tried to breach a barrier at the White House, setting off a high-speed car chase that put the Capitol on lockdown and ended with her being shot dead by police.

The harrowing chase Thursday unfolded between two national landmarks, briefly shuttered the chambers where federal lawmakers were debating how to end a government shutdown and stirred fresh panic in a city where a gunman two weeks ago killed 12 people.

Police said there appeared to be no direct link to terrorism and there was no indication that the woman was even armed. Capitol Police Chief Kim Dine, whose officers have been working without pay as a result of the shutdown, called it an “isolated, singular matter.”

Still, tourists, congressional staff and even some senators watched anxiously as a caravan of law enforcement vehicles chased a black Infiniti with Connecticut license plates down Constitution Avenue outside the Capitol and as officers with high-powered firearms canvased the area. The House and Senate both abruptly suspended business, a lawmaker’s speech cut off in mid-sentence, as the Capitol Police broadcast a message over its emergency radio system telling people to stay in place and move away from the windows.

The woman’s car at one point had been surrounded by police cars and she managed to escape, careening around a traffic circle and past the north side of the Capitol. Video shot by a TV camerman showed police pointing firearms at her car before she rammed a Secret Service vehicle and continued driving. Metropolitan Police Chief Cathy Lanier said police shot and killed her a block northeast of the historic building.

Two law enforcement officials identified the female driver as 34-year-old Miriam Carey, of Stamford, Conn. She was traveling with a 1-year-old girl who avoided serious injury and was in protective custody late Thursday. The officials spoke on condition of anonymity because they were not authorized to discuss an ongoing investigation.

The FBI served a search warrant in connection with the investigation and police cordoned off a condominium building and the surrounding neighborhood in the shoreline city.

Condo resident Eric Bredow, a banker, said police told him the suspect in the car chase was one of his neighbors.

“I see the door to my building open and the FBI bomb squad in front of it,” said Bredow, who said helicopters were flying overhead when he first went home

The chain-of-events began when the woman sped onto a driveway leading to the White House, over a set of barricades. When the driver couldn’t get through a second barrier, she spun the car in the opposite direction, flipping a Secret Service officer over the hood of the car as she sped away, said B.J. Campbell, a tourist from Portland, Ore.

“This wasn’t no accident. She was not a lost tourist,” Campbell said later near the scene that had been blocked off with police tape.

Then the chase began.

“The car was trying to get away. But it was going over the median and over the curb,” said Matthew Coursen, who was watching from a cab window when the Infiniti sped by him. “The car got boxed in and that’s when I saw an officer of some kind draw his weapon and fire shots into the car.”

One Secret Service member and a 23-year veteran of the Capitol Police were injured. Officials said they are in good condition and expected to recover.

Rep. Michael McCaul, R-Texas, who said he was briefed by the Homeland Security Department, said he did not think the woman was armed. “There was no return fire,” he said.

A few senators between the Capitol and their office buildings said they heard the shots.

“We heard three, four, five pops,” said Sen. Bob Casey, D-Pa. Police ordered Casey and nearby tourists to crouch behind a car for protection, then hustled everyone into the Capitol.

Others witnessed the incident, too.

“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.

Capitol Police on the plaza around the Capitol said they were working without pay as the result of the shutdown. A spokesman for House Majority Leader Eric Cantor said a bill to pay them was under consideration.