The U.S. Capitol was placed under lockdown on Thursday following reports of gunshots outside the west front of the building, the Associated Press reported.

The House and Senate both stand in recess as authorities work to secure the complex. A spokesman with the FBI’s Washington, D.C. field office told TPM on Thursday agents were “responding to the scene.”

U.S. Capitol Police sent out the following notice to all Hill staff:

SHELTER IN PLACE. Gunshots have been reported on Capitol Hill requiring all occupants in all House Office Buildings to shelter in place. Close, lock and stay away from external doors and windows. Take annunciators, Go Kits and escape hoods; and move to the innermost part of the office away from external doors or windows. If you are not in your office, take shelter in the nearest office, check in with your OEC and wait for USCP to clear the incident. No one will be permitted to enter or exit the building until directed by USCP. All staff should monitor the situation. Further information will be provided as it becomes available.

Update: The lockdown of the U.S. Capitol was lifted at about 2:58 p.m. ET, officials announced, roughly 40 minutes after first reports of gunfire on the grounds.

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