The Cannon House Office Building was temporarily evacuated on Thursday after an alarm went off, forcing brief road closures surrounding nearby congressional buildings.
Capitol Police issued an all-clear shortly after 1 p.m., more than an hour after calling for staff and personnel to exit the building.
Two police officers said it seemed the evacuation was due to a fire alarm, though it was not immediately clear what prompted the alarm and subsequent evacuation.
The initial notice urged staff to remain calm and move toward exits in a safe manner. Capitol Police directed all staff and personnel to remain outside the building until further notice as they investigated.
Several roads surrounding the Capitol and congressional office buildings were shut down due to the evacuation, including portions of Independence Avenue, New Jersey Avenue, First Street and C Street.
Police cordoned off pedestrians walking near the building.
Cannon evacuation pic.twitter.com/3UPjlBrEcq— Olivia Beavers (@Olivia_Beavers) October 25, 2018
Fire trucks outside Cannon building pic.twitter.com/b3lkJsVcBu— Olivia Beavers (@Olivia_Beavers) October 25, 2018
The evacuation came amid heightened tensions over suspicious packages sent to multiple Democratic figures on Wednesday as well as the New York offices of CNN, which forced an evacuation.
Updated: 1:21 p.m.