Updated

The U.S. Capitol was put on lockdown on Monday morning due to an "external security threat" as the West Front of the Capitol, where the inauguration is slated to happen Wednesday, was evacuated. 

Washington D.C. Fire and EMS confirmed that there was a fire at a homeless camp at the 100 Block of H St SE, which was extinguished. The U.S. Secret Service said in a tweet that there is "no threat to the public." A loudspeaker announcement just after 11:20 a.m. said "external threat has concluded - return to normal operations."

Those inside the Capitol were told to stay away from external windows and doors but were permitted to continue to move around inside the buildings.

"Due to an external security threat under the bridge on I-295 at First and F Streets SE, staff and other personnel are directed to avoid coming to the Capitol Complex area until further notice," an alert from the U.S. Capitol Police, obtained by Fox News, read. "All personnel currently on the Capitol Complex are advised to stay indoors and away from windows and doors."

People evacuate from the West Front of the U.S. Capitol during a rehearsal the 59th Presidential Inauguration at the U.S. Capitol in Washington, Monday, Jan. 18, 2021. (AP Photo/Carolyn Kaster) (AP)

The scare Monday came as officials in Washington, D.C., are concerned about an insider attack from service members deployed to Washington, D.C., for President-elect Joe Biden’s inauguration.The concerns prompted the FBI to vet all 25,000 National Guard troops in the city, Fox News has learned.

The U.S. Army issued a statement late Sunday obtained by Fox News that said it is working with the Secret Service to determine if any service members on hand need additional background screening.

FAST FACTS

    • The Capitol attack resulted in dozens of arrests and prompted officials in the city to take drastic measures to ensure the Biden inauguration is secure.
    • Officials increased the number of National Guard members who will be deployed in Washington during the presidential inauguration from 15,000 to 20,000 on Wednesday

The statement said that all service members are familiar with the Threat Awareness and Reporting Program, which "requires department personnel to report any information regarding known or suspected extremist behavior that could be a threat to the department or the U.S."

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