SEOUL, Dec. 22 (Yonhap) -- Nineteen Chinese and Russian aircraft entered South Korea's air defense identification zone on Tuesday in what appeared to be a combined exercise, prompting the Air Force to scramble fighter jets, the Joint Chiefs of Staff (JCS) said.
Four Chinese jets first entered the Korean Air Defense Identification Zone (KADIZ) above the East Sea, followed by 15 Russian aircraft that flew in from north, according to the military.
The JCS said the two countries appeared to have conducted a combined training.
"Our military dispatched the Air Force fighter jets before their KADIZ entry in preparations for accidental situations," it said in a statement.
Before the aircraft's KADIZ entry, the Chinese military told South Korea its planes were carrying out normal training, according to officials.
Air defense identification zones are not territorial airspace and are not bound by international law. But a foreign warplane is supposed to make prior notification before approaching them in line with international customs to prevent accidental clashes.
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