An unarmed Russian Air Force three-engine jet flew over the U.S. Capitol at low altitude on Wednesday as part of a routine observation flight allowed under the Treaty on Open Skies, CNN reported.

Although routine, the intelligence-gathering operation is gaining fresh attention due to recent heightened tension between the U.S. and Moscow.

U.S. Capitol Police issued an alert on Wednesday announcing the flight of a "large" aircraft over Washington between 11 a.m. and 3 p.m., but did not say that the aircraft belonged to the Russian Air Force.

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United States Air Force personnel were on the flight, and the U.S. participates in the treaty along with 34 signatory nations.

The Russian Tupolev Tu-154 flew over a variety of restricted locations including the Pentagon, the Central Intelligence Agency and Trump National Golf Course in Virginia, and Andrews Air Force Base and Camp David in Maryland.

In its flight over downtown Washington, the aircraft was authorized to enter the secure airspace around the White House.

The same jet is also reportedly scheduled to fly over President Trump's golf resort in Bedminster, N.J., between 5 p.m. and 6 p.m. on Wednesday. The president is currently there on vacation.