(CNN) An unarmed Russian Air Force aircraft overflew the US Capitol, the Pentagon, Central Intelligence Agency and Joint Base Andrews at low altitude on Wednesday as part of a longstanding treaty that allows the militaries of the United States and Russia to observe the other from the air, according to two people familiar with the flight.

The flight was part of the Treaty on Open Skies, which allows military aircraft from the United States and Russia and other nations to fly aerial observation flights to observe military sites of the 34 signatory nations.

The Russian Air Force Tupolev Tu-154 on Wednesday afternoon passed at around 3,700 feet over downtown Washington and Joint Base Andrews in Maryland, where Air Force One is based, according to tracking website Flightradar24.

The jet is authorized to enter P-56, the highly secure airspace surrounding the White House.

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A second flight by the same jet is planned for between 5 p.m. and 6 p.m. Wednesday, when the Russian jet will overfly Bedminster, New Jersey, where President Donald Trump is vacationing, according to two people familiar with the US government-approved flight.

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