Seoul called in China's ambassador on Saturday after a Chinese military plane violated South Korea's air defense identification zone, officials said.

South Korean Deputy Foreign Minister Yoon Soon-gu summoned Chinese Ambassador Qiu Guohong and called for Beijing to come up with measures to prevent such a violation from happening again, ministry officials said.

Separately, the Defense Ministry said it called in Du Nongyi, military attache of the Chinese embassy in Seoul, and lodged a stern protest against the Chinese military plane's violation of the KADIZ.

According to Seoul's Joint Chiefs of Staff, the Chinese aircraft, believed to be a reconnaissance plane, entered the air defense zone in the northwest in the morning and stayed for about four hours.

"At 10:44 a.m., one Chinese military plane entered the KADIZ from northwest of Ieo Island," the JCS said in a statement, referring to the submerged rock south of Jeju Island.

It then changed direction near the southeastern port city of Pohang toward the eastern island of Ulleung before steering south and exiting the KADIZ on its entry route at 2:33 p.m., the JCS said.

The South Korean Air Force sent some fighter jets, including F-15K aircraft, to monitor the Chinese plane.

Through a direct communication line with Beijing, Seoul made a call for an end to any act that would escalate tensions and lead to accidental clashes, the JCS said.

The Chinese side is said to have claimed that it conducted "normal" flight training in international airspace within the confines of international law.

In February, a Chinese warplane also entered the KADIZ without any notification. (Yonhap)