Ahn Chan-myung, head of the Joint Chiefs of Staff's operations division, delivers a warning statement to North Korea at the Ministry of National Defense's headquarters in Yongsan-gu, Seoul, Thursday. (Yonhap)

South Korea's military said Thursday it staged airstrike drills against a mock mobile missile launcher earlier this week in an apparent warning against North Korea's latest firing of an intercontinental ballistic missile (ICBM).

The drills took place Wednesday at a training ground in Taebaek, 181 kilometers east of Seoul, as part of the ongoing Freedom Flag air exercise with the US, a day before North Korea launched an ICBM into the East Sea.

Hours after the launch, the Joint Chiefs of Staff (JCS) released images of the drills striking at least one mock transporter erector launcher with a laser-guided bomb in an apparent show of their readiness to take out North Korean missile vehicles.

North Korea has usually employed such vehicles to fire its ICBMs, which are theoretically capable of striking the US mainland.

The JCS also said the allies staged combined strike package drills on Thursday in response to the North's ICBM launch, which marked the first of its kind this year.

The US Air Force in South Korea said Thursday's drills involved four US F-16s flying in formation with four South Korean F-16s and conducting a "planned show-of-force" mission.

"Through this large-scale combined air exercise, our military demonstrated the South Korea-U.S. combined defense capabilities and posture that can overwhelm the enemy in preparation against North Korea's nuclear and missile threats," the JCS said in a release.

Freedom Flag, which takes place for the first time this year, kicked off its 12-day run on Oct. 21. It replaces the allies' two regular large-scale air drills -- Korea Flying Training in the first half of the year and Vigilant Defense in the second half. (Yonhap)