The U.S. has sent two B-1B strategic bombers to Korean skies for joint exercises with the South Korean Air Force on Tuesday, a Defense Ministry spokesman here told reporters.

A military source here said Gen. Vincent Brooks, the commander of the U.S. Forces Korea, gave unprecedented instructions to publicize the bombers' arrival. The USFK asked South Korea the previous day to assist with aerial photography.

Pictures of the bombers taking off from Guam and training in the sky over the Korean Peninsula were posted on the USFK and Pacific Air Forces Command Facebook pages.

Two Korean F-15Ks joined the drill, which took some three hours.