UPDATE: 5:45 p.m. EDT — Larry Dawson was issued a "stay away order" by D.C. Superior Court in October, ordering him to keep away from the Capitol grounds, months before be brought a gun to the U.S. Capitol Monday afternoon, court documents show. Dawson was arrested in 2015 for disrupting Congress and yelling out that he was a "prophet of God," according to media reports. He pleaded not guilty. 

UPDATE: 5:23 p.m. EDT — Video has emerged of the gunman who attacked the U.S. Capitol Monday that shows him yelling at House members last year. Larry Dawson of Tennessee was arrested in 2015 for disrupting Congress and yelling out that he was a "prophet of God,"  according to the Daily Beast

Dawson was receiving medical care Monday after he was shot by police. The vehicle he drove to the Capitol in was secured by police and was under investigation, according to media reports.  

UPDATE: 5:10 p.m. EDT — As a shooting unfolded at the Capitol Visitors Center in Washington Monday afternoon, chaos broke out, with visitors running and shouting, according to Jill Epstein, executive director of California Association of Marriage and Family Therapists, who was walking through the metal detectors when the shooter attacked. She told NBC News one of her colleagues left his watch, wallet and phone behind because they were on the metal detector conveyor belt when the shooting started.

"People started screaming, 'Get out! Get out!' We didn't know which way to run. We ran out and they told us to get against the wall, so we were crouching against the wall outside the visitors center," Epstein told NBC News.

"Police appeared out of everywhere and they were screaming, 'Run for it! Run for it! Run up that ramp!' And we ran like you see in videos. It was surreal," said Epstein. 

UPDATE: 4:55 p.m. EDT — Capitol Police Chief Matthew Verderosa told reporters that an unidentified male suspect was undergoing surgery after being shot by police at the Capitol Visitors Center. The suspect drew and aimed what appeared to be a weapon there just after 2:30 p.m. EDT. He was struck, taken into custody and transported to the hospital.

Verderosa also corrected earlier reports that said a officer had been shot — only the suspect and a female bystander were injured, he said.

"While this is preliminary information, based on the initial investigation we believe this is the act of a single person who has frequented the Capitol grounds before," Verderosa said. "There is no reason to believe this is anything more than a criminal act."

ABC News previously identified the man as Larry Dawson of Tennessee. Dawson was arrested in Washington last fall.

Nobody has been charged in connection with Monday's incident.

UPDATE: 4:26 p.m. EDT — ABC News identified the suspect in the United States Capitol shooting Monday as Larry Dawson of Tennessee. He was arrested in the House last year after an incident in which he yelled that he was a "prophet of God," according to the Daily Beast.

The D.C. Courts website has a record for a Larry Russell Dawson who was charged with assault on a police officer and unlawful conduct on Capitol grounds in October 2015. He failed to appear in court.

UPDATE: 4:13 p.m. EDT — First Street and East Capitol Street in Washington were closed Monday afternoon as law enforcement continued to investigate a shooting at the U.S. Capitol, the Senate Sergeant at Arms Office tweeted. 

The Capitol Police were set to host a news conference about the incident at 4:15 p.m. EDT. Watch it below or here.

UPDATE: 4:04 p.m. EDT — Anonymous federal law enforcement officials told the New York Times Monday they didn't think Monday's shooting at the United States Capitol was "part of a larger plot." An area lockdown had also been lifted, NPR reported.

The White House's earlier lockdown was "a routine precautionary measure" after news broke of the Capitol incident, Secret Service spokesman Robert Hoback told BuzzFeed in a statement.

UPDATE: 3:50 p.m. EDT — Reports appeared to disagree Monday afternoon about how many people were injured in a shooting at the United States Capitol Building. According to CNN, only one woman was hurt by shrapnel. But the Associated Press reported one Capitol police officer was wounded.

UPDATE: 3:39 p.m. EDT — A number of lawmakers took to Twitter Monday afternoon to reassure followers their staff members were safe after a shooting at the United States Capitol Building. Rep. Pete Olsen, R-Texas, and Sen. Chris Murphy, D-Conn., were among the politicians tweeting that their personnel were OK.

The Associated Press reported that one Capitol police officer had been shot and a suspect taken into custody.

The area had undergone a lockdown drill earlier in the day, generating confusion Monday afternoon, according to the Daily Beast.

UPDATE: 3:27 p.m. EDT — The official Twitter account for the D.C. Metropolitan Police confirmed Monday afternoon there had been "an isolated incident" at the United States Capitol building. "There is no active threat to the public," it wrote. The Associated Press had previously reported that one Capitol police officer had been shot, but not seriously hurt.

According to CNN, a White House lockdown that occurred around the same time as the Capitol's was in reaction to a different incident. The cable channel reported that it involved a person trying to jump the fence.

UPDATE: 3:18 p.m. EDT — CBS News reported that lockdowns at the Capitol and White House had been lifted after a shooting nearby. Congress was on recess, but the White House was hosting its annual Easter Egg Roll Monday.

WJLA has a live stream from the scene here.

UPDATE: 3:08 p.m. EDT — One person was in custody Monday afternoon after allegedly shooting a police officer near the United States Capitol building, the Associated Press reported. The officer was not critically injured.

The U.S. Capitol's official Facebook page had not yet posted about the incident, but reports continued to persist on social media. Congress is on recess.

UPDATE: 3:03 p.m. EDT — The verified Twitter account of the U.S. Senate Sergeant at Arms Office confirmed the Capitol complex's shelter-in-place order Monday afternoon after reports of a shooting. The Associated Press reported the White House had also been locked down.

Original story:

Users on social media reported that shots had been fired and they'd gone on lockdown at the United States Capitol building Monday afternoon. The Metropolitan Police Department confirmed a report of a shooting near the Capitol to ABC 7, but further details were unclear as of 2:55 p.m. EDT.

The Daily Beast reported paramedics were en route "to treat multiple injuries," and a reporter for WUSA9 tweeted that a "shooter is down," citing a Capitol Police source.

This is a developing story. Check back for updates.