North Korean leader Kim Jong Un has overseen air force drills "under the simulated conditions of real war," state-run media reported Monday, a day after the U.S. and South Korea said they were postponing their joint air exercises in a bid to boost stalled nuclear talks with Pyongyang.

The defense chiefs of the U.S. and South Korea said Sunday they would postpone upcoming military drills in an effort to bolster a stalled peace push with North Korea.

The U.S. denied that the planned drills, which had already been scaled back from previous years, would have amounted to another concession to North Korea. The U.S. has already canceled, postponed or scaled back a number of its joint military exercises with South Korea.