The woman who led the chase was shot and killed, police said at an evening news conference. The woman was identified as 34-year-old Miriam Carey of Stamford, Conn.
Police originally said the police officer was injured when his cruiser was struck by a woman fleeing police in a late-model black car, apparently with a child inside, but later said he had struck a barrier while giving chase. Neither his injuries nor those of the Secret Service agent were life-threatening, police said.
Video on CNN showed police running with the child, who was taken to the hospital with serious but non life-threatening injuries.
The chase began at a checkpoint to get onto the White House grounds and ended about 2:20 p.m. outside the Hart Senate Office building with the shots fired.
Amateur video showed police shooting at the car after it was cornered somewhere between the White House and the capitol. The driver rammed a police car and nearly ran over officers before speeding off.
The Capitol building was placed on lockdown just after the shots were fired, according to the Associated Press. It was lifted less than an hour later.
Tourist Edmund Ofori-Attah told the AP he walked toward the car when it crashed.
"Then I heard the gunfire" and hit the ground, he said.
CNN reported the injured officer was air-lifted to a hospital.
Scenes of roads closed and dozens of police cars and other emergency vehicles were strikingly reminiscent of the scene just a short distance away, at the Washington Navy Yard, where 12 people were gunned down and killed less than three weeks ago.
In Thursday's incident, Virginia Rep. Gerry Connolly was standing on a balcony of the U.S. Capitol with Rep. Matt Cartwright of Pennsylvania when they heard two bursts of gunfire coming from the direction of the Rayburn Office Building, The Washington Post reported.
“It was almost like two very rapid fire bursts, very loud,” Connolly told the Post. “They were clearly coming from the direction. That’s when we saw people fleeing, and we realized this was no fireworks. It sounds liked the first volley of a 21-gun salute.”
He said he could see people fleeing from the Rayburn building and police officers running toward it before he was shepherded back into the building. Connolly told the paper he was told by the Sergeant-at-Arms that a suspect has been apprehended.
Capitol Police had sent out the following advisory to staffers:
"SHELTER IN PLACE. Gunshots have been reported on Capitol Hill requiring all occupants in all House Office Buildings to shelter in place. Close, lock and stay away from external doors and windows. Take annunciators, Go Kits and escape hoods; and move to the innermost part of the office away from external doors or windows. If you are not in your office, take shelter in the nearest office, check in with your OEC and wait for USCP to clear the incident. No one will be permitted to enter or exit the building until directed by USCP. All staff should monitor the situation. Further information will be provided as it becomes available."