WASHINGTON – A Russian surveillance plane soared through secure airspace over Washington on Wednesday, presumably collecting intelligence as it traveled near the Pentagon, the Capitol and other government buildings, two U.S. officials said.

The Russian Air Force Tupolev Tu-154 aircraft made the flight through the Treaty on Open Skies, which Russia, the United States and 32 other nations have signed. The treaty established criteria under which countries can make unarmed observation flights over the soil of other treaty members in an effort to promote transparency and international arms control efforts.

The Capitol Police issued an alert Wednesday that warned that an “authorized low-altitude aircraft” would enter restricted airspace between 11 a.m. and 3 p.m.

“This flight will be monitored by U.S. Capitol Police and other federal government agencies,” the alert stated.

A Defense Department official, speaking on condition of anonymity, confirmed that the flight alluded to was Russian.

The flight, first reported by CNN, is expected to be followed by another one Wednesday that flies over President Trump’s property in Bedminster, New Jersey. According to the treaty guidelines, U.S. airmen are aboard the Russian jet observing.

But Marine Lt. Gen. Vincent Stewart, director of the Defense Intelligence Agency, has argued that Russia may be taking advantage of the treaty. He told the House Armed Services Committee subcommittee on emerging threats and capabilities last year that he would “love” to deny future Russian flights over the United States through Open Skies.