The US Capitol complex and White House were locked down after reports of an active shooter on Capitol Hill. Members of Congress and the tourists visiting the building were told to shelter in place.

No one is allowed to enter or exit any of the buildings in the congressional complex. Anyone outside was advised to “seek cover immediately,” local media reported.

US Capitol Police source tells me shooting at visitor center - and "shooter is down." @wusa9 — Ellison Barber (@ellisonbarber) March 28, 2016

Shots were reportedly fired at the Capitol Visitor Center, an underground facility on the east side of the main building.

Capitol barricades activated on Independence Ave pic.twitter.com/uJzPan1ffB — Scott Wong (@scottwongDC) March 28, 2016

Citing the Capitol’s Sergeant at Arms, local media reported one police officer was shot, but “not seriously."

Subsequent reports said the officer was not shot, but maybe injured by debris, and had been treated at the scene. CNN reported that one female civilian was injured by "shrapnel."

This was confirmed by Capitol Police Chief Mathew Verderosa, who told reporters Monday afternoon that an "uninvolved female bystander suffered what appeared to be minor injuries.”

No officers were injured, Verderosa added.

ABC News has identified the suspect as Larry R. Dawson, a resident of Tennessee. Authorities believe he is the same man who burst into the House chambers in October 2015 and shouted he was a"prophet of God."

Verderosa, who did not name the suspect, said he was currently undergoing surgery and his condition was unknown.

Heavy police and fire response to a reported shooting in the Capitol. Helicopters now too. #Capitolshootingpic.twitter.com/3y19CxlxQD — Ron Haskell (@RonHaskell) March 28, 2016

The White House was placed on lockdown as well.

Shelter in place “remains in effect” while the Capitol Police investigate the incident, the Sergeant at Arms told Roll Call around 3:20 p.m. local time. The lockdown was officially lifted half an hour later.

BREAKING: Capitol gunman captured; one police officer shot and not seriously injured pic.twitter.com/00PqmGBYom — Arele Schapiro ️️ (@areleschapiro) March 28, 2016

According to NBC correspondent Pete Williams, the suspect entered the Capitol Visitors’ Center and pointed a gun at the police officer, who took him down with a single shot. The suspect has been taken to an area hospital.

Citing unnamed sources at the Capitol, NBC later reported that the suspect pulled out his weapon when it triggered the metal detector inside the visitor center.

Not good A video posted by Sammy Sanchez (@ssammysanchez) on Mar 28, 2016 at 12:12pm PDT

Bad picture but this is rapper @TheRealSilento being escorted off the WH grounds. He was supposed to perform this hr pic.twitter.com/Yygh54hqAj — Benny (@bennyjohnson) March 28, 2016

Tourists were allowed to leave the Capitol around 3:30 p.m. local time.

Like an exodus. Tourists being allowed to leave Capitol complex after shooting pic.twitter.com/XJwZfnHL3F — Scott Wong (@scottwongDC) March 28, 2016

Initial reports of a shooter caused some confusion because the Capitol complex had held an active shooter drill earlier in the day.

At the time of the incident, the Congress was not in session. According to the Senate Sergeant at Arms, the Senate convened today for a pro forma session, but remains adjourned until March 31.

The Capitol Visitor Center will remain closed until further notice. The facility was built to improve security after a mentally ill shooter killed two Capitol Police officers in 1998.