US Spy Plane Sweeps North Korean Border

An American surveillance aircraft performed a full sweep of the Korean Peninsula’s heavily armed demilitarized zone last week on the same day North Korean leader Kim Jong Un was said to have overseen the test of new ballistic missile technology.

Aircraft signals received by the website Flightradar24, a favorite among plane spotters, showed a U.S. Air Force RC-135U Combat Sent flying a nearly nine-hour sortie on May 17, cutting across the peninsula from the East China Sea to the Sea of Japan—known in both Koreas as the East Sea.

The long-endurance reconnaissance platform equipped to gather electronic intelligence flew out of Kadena Air Base in Okinawa, the Western Pacific island that hosts about two-thirds of the 50,000 or so U.S. troops stationed in Japan.

Newsweek‘s map traces the Combat Sent’s hourslong mission across Northeast Asia on Friday, a journey that covered at least 2,300 miles, according to rough estimates, or about half its stated operational range.

At about noon that day, the spy plane had reached the Sea of Japan, and it doubled back at least once before returning to Okinawa.

The same aircraft has deployed to the Chinese coast several times this month.

The Combat Sent, which the Air Force says collects signals from foreign military hardware for analysis, was about 40 miles south of the de facto inter-Korean border, according to Flightradar24, or 100 miles south of Wonsan, the North Korean port city and naval base where Pyongyang’s latest test was conducted.

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South Korea’s Joint Chiefs of Staff first reported the launch of short-range ballistic missiles from Wonsan toward the Sea of Japan on Friday, but the test fire was not acknowledged by the North until a day later.

Pyongyang’s state-owned Korean Central News Agency said on Saturday that Kim had overseen a “tactical ballistic missile” test that verified a “new autonomous navigation system.”

“The test fire is part of the regular activities of the administration and its affiliated defense science institutes for rapid technological development of weapon systems,” KCNA said.

The U.S. Defense Department does not comment on specific operations. It was therefore unclear whether the Combat Sent’s sortie along the DMZ was related to the launch event.

North Korea’s embassy in Beijing did not immediately return a written request for comment.

On Friday, KCNA reported Kim’s visit to a manufacturer of missile launcher vehicles, which North Korea’s state media linked to the regime’s “nuclear war deterrent.”

North Korea’s enemies, Kim was quoting as saying, “would grow dreadful and dare not to play with fire only when they witness the nuclear combat posture of our state,” in language that has typified the recent months of high tensions on the peninsula.