Nine Chinese and Russian military aircraft briefly entered and left South Korea's air defense identification zone (KADIZ) above waters east and south of the country, South Korea's military said Tuesday.

Axar.az informs, citing Yonhap, two Chinese military planes and seven Russian aircraft successively entered the KADIZ at around 10 a.m. prompting the military to dispatch Air Force fighter jets in preparation for a possible accidental situation, according to the Joint Chiefs of Staff (JCS).

They did not violate South Korea's air space, the JCS said, adding it detected the aircraft before they entered the air defense zone.

The air defense zone is not territorial airspace but is delineated to call on foreign planes to identify themselves so as to prevent accidental clashes.

The aircraft, including bombers and fighter jets, intermittently entered and left the KADIZ for about an hour before completely retreating from the air defense zone, a JCS official said.

Since 2019, the two countries have sent their military planes into the KADIZ once or twice a year during joint exercises, without prior notice.

In the last such incident, 11 military planes from both China and Russia entered the KADIZ together in November last year.