The U.S. Capitol underwent a lockdown on Monday after reports of an "external security threat," prompting evacuations and warnings sent to staff.
Per NBC News, staff at the Capitol were sent a message to inform them of the developing situation. "All buildings within the Capitol Complex: External security threat, no entry or exit is permitted, stay away from exterior windows, doors," the message read. "If outside, seek cover."
A follow-up message later indicated it was "an external security threat located under the bridge on I-295 at First and F Streets SE."
Reports from law enforcement suggested the evacuation was in response to what turned out to be a fire at a homeless encampment, NBC's Pete Williams said. The Washington, D.C. fire department also confirmed there were no injuries at the scene.
CBS News reports that Capitol Police acting chief Yogananda Pittman issued the shutdown due to "an abundance of caution." Police added, "There are currently no fires on or within the Capitol campus. Members and staff were advised to shelter in place while the incident is being investigated."
The U.S. Secret Service announced that the fire has since been extinguished, and there's currently "no threat to the public."
The lockdown comes as part of what is expected to be a tense week in the Capitol, with security increased significantly in response to the Jan. 6 insurrection that saw far-right domestic terrorists storm the building. Many have since been arrested, although some have asked Donald Trump for a pardon. Trump was heavily criticized for inciting violence, and subsequently impeached and banned from Twitter for his complicity.