US spy flight reported near North Korea border following claim of underwater nuclear drone

A U.S. spy aircraft was detected flying near North Korea following the reclusive nation's claim to possess underwater nuclear-capable drones, South Korean media claims.

The U.S. Air Force RC-135W Rivet Joint was detected above the South Korean city of Incheon near the capital of Seoul, according to Yonhap News Agency. It was also reportedly detected over the Gyeonggi and Gangwon provinces.

Gyeonggi and Gangwon provinces border the demilitarized zone (DMZ) separating North Korea and South Korea.

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In this picture taken near the truce village of Panmunjom inside the demilitarized zone (DMZ), a North Korean flag flutters in the wind at the propaganda village of Gijungdong. (Anthony Wallace/AFP via Getty Images)

The alleged detection of the aircraft follows escalating tensions caused by North Korean claims that supreme leader Kim Jong Un's regime has produced nuclear-capable underwater drones.

North Korea claimed it tested a drone designed to destroy naval vessels and ports on Friday via state media.

North Korea’s military said it conducted the test in the country’s eastern waters in response to naval drills by the U.S., South Korea and Japan, which ended Wednesday. 

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The underwater drone is among a broad range of weapons systems Kim Jong Un continues to test and develop as he expands his arsenal of nuclear-capable weapons.

North Korean leader Kim Jong Un speaks at the Supreme People’s Assembly in Pyongyang, North Korea. (Korean Central News Agency/Korea News Service via AP)

North Korea did not specify when the test occurred. It first tested the drone last year.

"Our army’s underwater nuke-based countering posture is being further rounded off and its various maritime and underwater responsive actions will continue to deter the hostile military maneuvers of the navies of the U.S. and its allies," North Korea’s Defense Ministry said in a statement.

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Other U.S. flights were reported on Jan. 4 and Jan. 17, part of routine intelligence routes in the region, according to reports.

Fox News Digital's Lawrence Richard contributed to this report.