Capitol Building on Lockdown; Police Investigating (UPDATED)

The U.S. Capitol was put on on lockdown Tuesday afternoon, according to multiple reports.

BREAKING: US Capitol, visitors center on lockdown with police investigating.

— The Associated Press (@AP) July 12, 2016

Police are investigating and initially told people to shelter in place, stay away from windows, and not to leave the building.

An alert from the U.S. Capitol Police went out around 4:15 p.m.: “LOCKDOWN – Police activity has been reported on Capitol Hill.”

In Cannon rotunda and cops say we can’t leave the building … On lockdown pic.twitter.com/TOVDUcgBWb

— Molly Hooper (@mollyhooper) July 12, 2016

According to one report, two people are in custody following a shooting near the Department of Labor.

#BREAKING 2 in custody in shooting near the Department of Labor. Capitol on lock down.

— Henry Rodgers (@henryrodgersdc) July 12, 2016

This is the second time this has happened this week. The Capitol was also put under lockdown last Friday.

As of 4:35 p.m., people seem to be allowed to move within the building but cannot go outside.

Announcement just told us we can move around the building, but can enter or exit, and to stay away from windows. Capitol still on lockdown

— Jacqueline Klimas (@jacqklimas) July 12, 2016

Person inside Capitol complex says buildings are open, people just can't leave.

— David Charns (@DavidWMTW) July 12, 2016

DETAILS: DC police confirm they received a call about "man with a gun" near the US Capitol. https://t.co/bGgSGXsnyN pic.twitter.com/w124riQVEC

— RT America (@RT_America) July 12, 2016

As of 4:47 p.m., the lockdown has reportedly been lifted.

Capitol lockdown is ALL CLEAR.

— Steven Portnoy (@stevenportnoy) July 12, 2016

This story has been updated.