U.S. Capitol Police said Wednesday afternoon officers are searching in and around Senate office buildings after a “concerning 911 call,” reporting a possible active shooter.

Capitol Police noted they do not have any confirmed reports of gunshots, and asked those inside the Senate buildings to shelter in place.

“Please stay away from the area as we are still investigating,” U.S. Capitol Police wrote on X, formerly known as Twitter.

Staff in the Senate buildings were told to move inside their offices or to a nearest office, and close and lock external doors and windows.