South Korea said it urgently deployed its fighter jets after two Chinese and six Russian military planes entered the country¾«¶«Ó°Òµ Air Defense Identification Zone (KADIZ).
The warplanes, consisting of two Chinese H-6 bombers, four TU-95 strategic bombers and two SU-35 fighters, were spotted entering South Korea¾«¶«Ó°Òµ KADIZ off South Korea’s southern and northeast coasts on November 30, 2022, the country¾«¶«Ó°Òµ Joint Chiefs of Staff (JCS) were cited as saying by
South Korea deployed several fighter jets, including F-15K fighters, as a preventive tactical measure in case of any contingencies.
Meanwhile, the Japanese Ministry of Defense also announced that a similar incident had taken place on the same day after two Chinese H-6 bombers and two aircraft presumed to belong to Russia were spotted flying over the East Sea. It was later revealed that the Chinese and Russian warplanes were conducting a joint training exercise.
The air defense identification zone is a line arbitrarily set by South Korea in order to be able to respond to military aircraft approaching into its own airspace at an early stage and is a different concept from airspace. 
As per international practice, a foreign military aircraft intending to enter another country’s air defense identification zone must submit a flight plan to the country¾«¶«Ó°Òµ authorities in advance and notify its location upon entry.