Seven people fall ill after 'suspicious package' delivered to Air Force One base

The package, delivered to Joint Base Andrews on Thursday, contained an unknown "white powder" and political propaganda.

Those affected by the white powder were taken to the on-base Malcolm Grove Medical Center.

A building on the base, located outside Washington, DC, was evacuated after the package was opened.

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A statement from Joint Base Andrews said: "As a precaution, the building and connecting building were evacuated, and a cordon was established around the area," the statement said.

"Joint Base Andrews first responders were dispatched to the scene, determined there were no immediate threats, and have turned the scene over to Office of Special Investigations.

"An investigation is currently ongoing."

Sources familiar with the incident told CNN that following an initial investigation, a HAZMAT team did not detect anything hazardous.

But teams are still working to identify the nature of the white substance.

The individuals taken to the hospital have been treated and subsequently released.

The political propaganda is also still being assessed by investigators.