An intruder broke into Joint Base Andrews in Maryland, where presidential Air Force One planes are kept, and was soon fired upon by a base resident Monday.

The individual gained access to the base Monday morning, before being spotted at a housing area inside the base. JBA houses AF1 jets and other presidential aircraft. A base resident inside the building fired a single shot, and then security arrived to arrest the man. He remains unidentified. 

"A man gained unauthorized access to a JBA housing area. A resident discharged a firearm, security forces arrived on scene to apprehend the intruder and law enforcement is investigating the incident," Joint Base Andrews said in a statement posted to Twitter.

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Air Force One

An unidentified intruder broke into the hangar where Air Force One craft are kept in Maryland. (iStock)

Joe Biden speaks with reporters

President Joe Biden speaks to the media as he arrives at Joint Base Andrews, Maryland. (Reuters/Jonathan Ernst/File)

In addition to Air Force One planes, hangars at the base house the massive "doomsday" plane that could serve as a mobile command center for the president in the event of major emergency, according to The Associated Press.

Officials have not stated the man's motive for entering the facility, though their investigation is ongoing.

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U.S. presidents have used Joint Base Andrews as the home of Air Force One for decades. President Biden and others frequently fly from the White House to the Maryland base on Marine One before taking longer trips on the presidential jet.

U.S. President Donald Trump waves while boarding Air Force One

President Donald Trump waves while boarding Air Force One at Joint Base Andrews. (Erin Schaff/Pool via Bloomberg)

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Biden has often used the base to fly to his homes in Wilmington and Rehoboth Beach, Delaware.

The Associated Press contributed to this report.