US and South Korean airmen have started a five-day combat drill to enhance their defense against aerial attacks.

Over 20 fighters from both countries flew counter-air drills for Ssangmae Training, or Buddy Squadron, from Osan Air Base.

The aircraft used in the drills include F-16 Fighting Falcons from Osan’s 51st Fighter Wing and F-15K Slam Eagles from South Korea’s 11th Fighter Wing.

The annual air drill began in 1998 and aims to respond to enemy provocations.

A separate 11-day joint military exercise, Freedom Shield, also began on Monday, aims to counter North Korean threats, such as its cruise-missile launch sites.

The US Forces Korea and the Ministry of National Defense have announced that this year’s exercise will consist of 48 drills, double the number conducted in 2023.

The exercise is anticipated to involve troops from various member states including Australia, Belgium, Canada, Colombia, France, Great Britain, Greece, Italy, New Zealand, the Philippines, and Thailand.

The drills come as diplomatic relations between North and South Korea have stalled, with both countries withdrawing from a military deconfliction agreement in November.

North Korea has recently fired a ballistic missile and cruise missiles, causing tensions between the two nations.