South Korea scrambled fighter jets after five Chinese military aircraft entered the country's Air Defense Identification Zone, or KADIZ, on Dec. 18.
The deployment of two Chinese bombers, two fighters jets, and a reconnaissance plane follows South Korean President Moon Jae-in's summit with Chinese leader Xi Jinping.
A South Korean Joint Chiefs of Staff official said the Chinese planes entered Korea-claimed airspace from the southwest — and also flew into Japan's Air Defense Identification Zone, or JADIZ, South Korean newspaper Maeil Business reported.
An armed Chinese fighter jet flies near a U.S. Navy P-8 Poseidon patrol aircraft over the South China Sea about 135 miles east of Hainan Island in international airspace. (U.S. Navy Photo)
"After our military noticed the aircraft approaching the KADIZ from the west, we used a hotline with the Chinese military to confirm whether or not it was Chinese military aircraft, and to take countermeasures," the South Korean official said.
South Korea scrambled F-15K and KF-16 fighter jets in response to the incoming flights — two Chinese H-6 fighter jets, two J-11 fighters, and one TU-154 reconnaissance aircraft.
Chinese aircraft last flew in Korea-claimed airspace on Jan. 9, when they deployed six H-6K bombers, a KJ-200, a propeller airborne early warning and control aircraft, and a Y-9 reconnaissance plane.
The Chinese flights came as Beijing's foreign ministry said the summit between Xi and Moon was a "success," South Korean news agency Yonhap reported.
Ministry spokeswoman Hua Chunying said the two sides agreed to "improve and develop the relationship" and to "respect the interests of our neighbors."
The summit in Beijing was eclipsed by brutal beatings of South Korean photojournalists, which were met with protests in Seoul.
"Chinese security guards kicked Korean journalists in the face and engaged in a group attack," protesters said Dec. 15. "It is a barbarous act, and it is hard to believe it could happen in a civilized country."