Update 3:45 p.m.: Police say suspect in custody after shooting outside Capitol, condition not disclosed.
Update 3:38 p.m.: Police says shooting at Capitol an isolated incident, not terrorism.
To hear the 3:06 p.m. interviews with Noah Bierman of the Boston Globe and NPR's Ron Elving, click the audio at the top of the page.
Update 3:20 p.m.: A law enforcement official says a shooting at the United States Capitol is related to a vehicle that tried to ram a security barricade at the White House.
The official says a driver tried to drive through a barricade that blocks the stretch of Pennsylvania Avenue in front of the White House to vehicles. The driver then proceeded down Pennsylvania Avenue to Capitol Hill, where shots were fired.
The official was not authorized to publicly discuss the incident by name and insisted on anonymity.
Update 3:18 p.m.: Police have now ended the lockdown at the U.S. Capitol building.
3:00 p.m.: A police officer is reported hurt after gunfire today at the U.S. Capitol building.
The Senate's Sergeant at Arms, Terrance Gainer, says, "There are reports of injuries." FBI agents headed to the scene.
The entire complex was put on lockdown.
As the warning was sounded, the House abruptly went into recess and lawmakers left the chamber floor. The House had just finished approving legislation aimed at partly lifting the government shutdown by paying National Guard and Reserve members.
Across the street, people standing outside the Supreme Court were hurried into the court building.
The White House was quickly locked down after the incident, and the stretch of Pennsylvania Avenue in front of the compound was closed to pedestrians.
The gunfire comes two weeks after a deadly shooting at the Navy Yard, near the Capitol.
This segment aired on October 3, 2013.