The country's first domestically developed supersonic fighter jet, the KF-21, will begin mass production this year.

The Defense Acquisition Program Administration(DAPA) said on Wednesday that it plans to sign the first production contract within the year and begin manufacturing the KF-21 fighters, with the first completed plane expected to be in service by 2026.

With the KF-21 successfully conducting test flights up to the sixth prototype last year in addition to passing various tests, such as supersonic flight and air-to-air weapons separation, the plane was judged to be provisionally suitable for combat.

DAPA is also conducting extreme environmental tests through next month to verify whether the aircraft and avionics equipment operate normally in extreme conditions such as high heat, cold and rain.