SEOUL --- A Chinese military aircraft entered South Korea's air defense domain again without notice Monday, defense authorities in Seoul said.
It entered the Korea air defense identification zone (KADIZ) at around 10:03 a.m. and flew out of it about half an hour later toward Ieo Island, a Seoul-controlled submerged rock south of Jeju Island, according to the Joint Chiefs of Staff.
It marked the sixth unilateral crossing of the KADIZ by Chinese warplanes this year alone.
An air defense identification zone, or ADIZ, is territorial sky declared by a state for the early identification and location of foreign planes approaching its territory. It's not defined in any international law or treaty.