WASHINGTON — A "small fire" under a nearby bridge prompted the temporary shutdown of the U.S. Capitol complex and the evacuation of the west front of the building, where a rehearsal for Wednesday's inaugural ceremony was underway Monday.
"Public safety and law enforcement responded to a small fire in the area of 1st and F streets SE, Washington, D.C. that has been extinguished," the Secret Service tweeted. "Out of an abundance of caution the U.S. Capitol complex was temporarily shutdown. There is no threat to the public."
President-elect Joe Biden and Vice President-elect Kamala Harris were not at the Capitol when the incident occurred. Both are participating Monday in service events to mark Martin Luther King Jr. Day. Biden and his wife are helping to distribute goods at Philabundance, Philadelphia's largest hunger relief organization, while Harris and her husband are volunteering in D.C.
Yogananda Pittman, acting chief of Capitol Police, acted out of "an abundance of caution following an external security threat under the bridge on I-295 at First and F Streets," and ordered a shutdown of the Capitol complex, according to a statement from Capitol Police.
"Members and staff were advised to shelter in place while the incident is being investigated."
Capitol Police later gave the all-clear, lifting the shelter-in-place advisory.
A law enforcement official told NBC News that the evacuation was prompted by what turned out to be a fire at a homeless encampment.
Washington, D.C.'s fire department tweeted about an incident that appeared to match that description.
Details of the incident came after an announcement was made across the Capitol that said that there was an external security threat and that people should stay where they are, and to stay away from doors and windows.
Download the NBC News app for breaking news and politics
A notice sent to House and Senate offices said, “All buildings within the Capitol Complex: Due to an external security threat located under the bridge on I-295 at First and F Streets SE, no entry or exit is permitted at this time. You may move throughout the buildings but stay away from exterior windows and doors. If you are outside, seek cover.”
Washington is on a high state of alert as Biden's swearing-in approaches after the Jan. 6 events that led to the violent storming of the Capitol by a pro-Trump mob.