Capitol put on lockdown after fire reported several blocks away

The Capitol complex was briefly locked down on Monday due to an “external security threat,” U.S. Capitol Police said, after a fire was reported several blocks away under a nearby bridge.

An email alert sent out to lawmakers shortly before 10:30 a.m. said that there was no entry or exit from the complex. Those inside the buildings were instructed to stay away from exterior windows and doors. Those outside were ordered to “seek cover.”

BREAKING: Entire Capitol complex including US Capitol on LOCKDOWN due to external security threat.

This email alert just went out to all lawmakers. Stay away from windows and doors. Seek cover if outside. pic.twitter.com/7n8CuCIqps

— Scott Wong (@scottwongDC) January 18, 2021

The lockdown went into effect as a rehearsal for President-elect Joe Biden’s Wednesday inauguration was underway, forcing people to be evacuated from the Capitol’s West Front and back into the building out of an abundance of caution.

Nearby reporters noted that smoke could be seen rising in the distance behind the Capitol.

BREAKING: Smoke rising behind Capitol building. Inauguration rehearsal appears to be evacuating. Emergency announcement playing at Capitol grounds. pic.twitter.com/86J9S8CsMY

— Jackson Proskow (@JProskowGlobal) January 18, 2021

A law enforcement official told NBC News that what turned out to be a fire at a homeless encampment prompted the security alert.

The D.C. Fire Department noted that a nearby fire was extinguished on the 100 block of H Street SE. No injuries were reported. 

#DCsBravest responded to an outside fire in the 100 block of H St SE that has been extinguished. There were no injuries. This accounts for smoke that many have seen.

— DC Fire and EMS (@dcfireems) January 18, 2021

Vito Maggiolo, a public information officer with D.C. Fire, told CNN that the fire was “very minimal” and it was “pretty much a non-incident.”

The Capitol is currently operating as a military zone ahead of Biden’s inauguration this week, as law enforcement ramped up security after a pro-Trump mob overwhelmed police to storm the building on Jan. 6, an attack that resulted in five deaths.

President Trump was impeached by the House last week on a charge of inciting an insurrection at the Capitol. 

There are currently 7-foot barriers that have been staged around the Capitol, its office buildings and the Supreme Court. The National Mall is temporarily closed to public access in the days leading up to and following the inauguration on Jan. 20. 

Roughly 25,000 National Guard troops are deployed to D.C. in order to boost security around the inauguration. Biden, Trump, Vice President Pence and lawmakers have been briefed on potential threats to the inauguration. Biden will be sworn in outdoors at the Capitol on Wednesday in a ceremony that has been scaled-down for health safety reasons during the coronavirus pandemic. 

Morgan Chalfant contributed.