(ATTN: ADDS more details on Seoul's protest in paras 7-10)
SEOUL, Feb. 23 (Yonhap) -- A Chinese military jet entered South Korea's air defense zone without notice three times Saturday, defense authorities said.
The aircraft entered the country's air defense identification zone, called the KADIZ, at around 8:03 a.m. near Ieo Island and exited at 8:27 a.m. according to the Joint Chiefs of Staff (JCS).
It re-entered the KADIZ at 9:34 a.m. near the southeastern city of Pohang, and flew between Ulleung and the easternmost islets of Dokdo, eventually leaving the air defense zone at 12:51 p.m.
The JCS said it marked the first time for a Chinese military plane to fly over the East Sea this year.
It also marked the first time for a Chinese military aircraft to fly between Ulleung and Dokdo.
The Air Force deployed fighter jets to track the aircraft and sent a warning message, the JSC said.
The South Korean defense ministry called in a military attache at China's embassy in Seoul to lodge a protest and call for measures to prevent any recurrence.
The defense ministry expressed concerns over the Chinese military jet's entrance into South Korea's air defense zone with prior notice.
The ministry delivered its message to the attache urging Beijing to take measures to prevent further recurrence and hold a working-level meeting to set up a military hotline between the two countries.
Seoul's foreign ministry also said it called in a Chinese official from the embassy here and expressed regrets while urging the taking of appropriate measures.
A section of the KADIZ overlaps with the air defense zones designated by China and Japan, a source of potential tension among the regional powers.
An air defense identification zone is an area of the skies declared by a state for the early identification and location of foreign planes approaching its territory. It is not defined in any international law or treaty.
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