A Russian surveillance plane flew multiple passes over Hawaii this week, likely snapping up imagery from the Kaneohe Bay Marine Corps base, in the approach to and at the entrance of Pearl Harbor, around much of the perimeter of Oahu and over parts of Lanai and Maui.

The Air Force’s 15th Wing at Joint Base Pearl Harbor- Hickam said the Russian Air Force Tupolev Tu-154M landed at Hickam on Wednesday to conduct the short-notice, unarmed observation flights through Thursday as part of the Treaty on Open Skies.

The international pact allows flights over the entire territory of other participants to verify arms control agreements and promote stability through transparency of military forces and activities.

Mutual aerial observation was first proposed by President Dwight D. Eisenhower in 1955 to reduce the risk of war, but the treaty itself became effective in 2002. Thirty-four countries are part of the agreement.

The National Defense Strategy says the central challenge to U.S. security is the reemergence of long-term, strategic competition from what the Pentagon calls “revisionist powers.”

“It is increasingly clear that China and Russia want to shape a world consistent with their authoritarian model — gaining veto authority over other nations’ economic, diplomatic, and security decisions,” the report says.

So it can still come as a shock to hear that a Russian surveillance plane is allowed to take imagery of U.S. military bases — or whatever Russia wants.

Time.com ran a story Friday with the headline “A Russian Spy Plane Was Spotted Over the Midwest. But It’s Totally Normal (Yes, Really).”

It was the same Tu-154M that eventually made its way to Hawaii via Moscow, Iceland, Canada and California. The three-engine jetliner was spotted by flight trackers as it flew past Dayton, Ohio, and over Chicago and Minneapolis.

“It reads like something out of a conspiracy theory,” the Time article said, adding that the United States “didn’t do anything to stop it.”

To be sure, the flights are not publicized, and many people are not aware they even occur. The Tu-154M flew approximately 2-1/2 hours over Hawaii, said Capt. Veronica Perez, a spokeswoman for the 15th Wing.

“There are U.S. Defense Threat Reduction Agency members on board escorting at all times who follow State Department guidance during these missions,” Perez said in an email. Friday was an extra day at Hickam planned in the event of bad weather.

Transponder signals collected by the site FlightRadar24 showed the Russians flew from California over the Waimanalo area Wednesday at about 7,900 feet and then over Waikiki before looping around and landing at Daniel K. Inouye International Airport.

That same day a flight looped around the southeast side of the island, returned back at about 6,000 feet over Waimanalo and passed over the southern coast — including Hickam and the entrance to Pearl Harbor — before doing a loop at sea off Kalaeloa and heading up the Waianae Coast and over the naval radio transmitter facility at Lualualei.

On Thursday the Tu-154M flew over Lanai and Maui, up along the east side of Oahu, including over the Marine Corps base at 4,975 feet altitude, and south of Waikiki and Pearl Harbor in a loop.

In 2016 Russia became the first treaty member to install approved digital electro-optical sensors on its Open Skies aircraft. The State Department said the treaty limits all optical sensors to 30-centimeter resolution — allowing differentiation of a truck from a tank.

In any event, the United States gets better imagery from its constellation of observation satellites. Russia also flew Hawaii overflights in 2017.

On Feb. 21 the United States conducted an Open Skies mission over Russia following a December flight over Ukraine, according to the Nuclear Threat Initiative.

On Wednesday, Russian aircrews posed with 15th Wing airmen at Hickam for a group photo.

“In theory, increased openness between militaries will reduce tensions between states and limit the probability of conflict,” the Center for Arms Control and Non-Proliferation said.