Officers from the United States Capitol Police (USCP) locked down or evacuated portions of the Capitol on Thursday morning to respond to reports of a suspicious vehicle near the Library of Congress in Washington, D.C., authorities said.
The USCP announced the suspicious activity on its Twitter page just after 9:40 a.m. local time and urged people to stay away from the area.
According to The Associated Press, police are investigating reports of a possible explosive inside a truck in the area.
The USCP called it an "active bomb threat investigation."
Aaron Fritschner, communications director for Rep. Don Beyer (D-Va), shared on Twitter screenshots of message alerts he had received from the police agency. One message sent at 9:53 a.m. states, "Madison: Internal Security Threat: move inside office/lock doors, seek cover, and remain silent."
A subsequent message states: "Jefferson: EVACUATE. Proceed to your designated assembly area. DO NOT exit out of the west side (First Street) of the building."
Other areas in the region have also been ordered to evacuate to neighboring buildings, Fox News has learned, but the entire Capitol is not currently locked down.
Police have said the investigation is ongoing. Meanwhile, many lawmakers are currently out of area for their August recess.