The South Korean military deployed fighter jets after eleven military aircraft belonging to China and Russia invaded the Korea Air Defense Identification Zone(KADIZ).

According to Seoul’s Joint Chiefs of Staff(JCS), five Chinese military planes and six Russian military planes consecutively entered KADIZ over the seas off the eastern and southern coasts without notice between 9:35 a.m. and 1:53 p.m. Friday.

There were no violations of South Korea’s airspace.

The JCS said the Air Force detected the aircraft even before they entered KADIZ and deployed the fighter jets as a tactical measure in case of contingencies.

While the air defense zone is not part of the country’s territorial airspace, foreign planes are urged to identify themselves before approaching the zone to prevent accidental clashes.