Joint Base Andrews in Maryland - the home to Air Force One - was placed on lockdown following a report of an active shooter. Officials subsequently said the report was false.
The base was placed on lockdown just after 9 am Thursday, officials at the base told News4. Vice President Joe Biden's travel schedule was interrupted as a result of the alert.
Reports said the suspected incident was said to have taken place at the Malcolm Grow Medical Facility. Emergency responders rushed to the scene.
All personnel were directed to shelter in place.
Subsequently, CNN reported that the report was not accurate. It appears that someone may have confused a drill that was taking place at the base on Thursday. The base also on Twitter that the situation had been declared "all clear".
Joint Base Andrews, in Prince George's County, Maryland, is the home of Air Force One and to other emergency reaction units for the area around the nation's capital.
Last month, Joint Base Andrews was placed on lockdown after a woman walked onto the base and claimed she had a bomb.
An Explosive Ordinance Disposal team found the woman had no explosives, and she was apprehended.
