Two Chinese military aircraft flew into South Korean and Japanese airspace on Sunday. Photo by Keith Tarrier/Shutterstock

SEOUL, Feb. 2 (UPI) -- Two Chinese military aircraft flew into South Korean and Japanese airspace, and Japan's Self-Defense Force fighter jets scrambled to intercept the planes.

Seoul's Joint Chiefs of Staff stated the two combat planes entered the Korea Air Defense Identification Zone, or KADIZ, on Sunday, Yonhap reported.


Kyodo News reported the aircraft were the Shaanxi Y-9 – a medium-size plane capable of transporting 25 tons of cargo.

The South Korea-identified airspace overlaps with China's, and China did not notify Seoul of its flight plans, South Korea said.

Jeon Ha-gyu, a spokesman for the South's Joint Chiefs, said South Korea detected the presence of unidentified aircraft in the area south of the peninsula. They were later identified as Chinese planes, and that they posed no military threat, Jeon said.

Jeon said Seoul took "necessary measures in surveillance and strategy" in response to China's planes, and that South Korea stands ready to respond to any incursions into exclusive South Korean airspace.

The two planes flew southwest of South Korea's Jeju Island, and after leaving KADIZ entered Japan's Air Defense Identification Zone, or JADIZ.

The planes flew over Tsushima Strait, an area between Korea and Japan before returning home, Kyodo News reported.

The Mainichi Shimbun reported Japanese fighter jets were dispatched to respond to the Chinese flying operation, and that it's likely the planes were on a mission to collect information on Japan's Aegis-class destroyers.

Japan is prepared to activate its "destroy on command" system should a North Korea missile enter Japanese airspace.