Two buildings have been evacuated at the base in Maryland, Axios reports.
It's unclear exactly what happened. Several individuals became ill after someone opened the package in question on Thursday, according to an email from an Air Force spokesperson that was reported by several media outlets. According to CNN's sources, the package contained a white powder.
The sick received treatment and their condition is considered stable. An investigation has been launched.
The presidential plane Air Force One landed at Joint Base Andrews as recently as Wednesday, when Donald Trump returned to the capital area from Florida.
