SEOUL, South Korea (AP) — The South Korean and U.S. militaries have agreed to shorten their drills at the U.S.'s request, South Korean officials said Wednesday, a move that likely reflected President Donald Trump’s hopes to reengage with North Korean leader Kim Jong Un but could undermine a U.S.-South Korean defense readiness. This was reported by Qazaqyia.kz citing Associated Press.

Trump had ordered his Pentagon chief to “substantially reduce” the allies’ summertime Ulchi Freedom Shield exercises, just before they began Monday for an 11-day run. Trump cited what he said was a good relationship with Kim and South Korea’s refusal to join the U.S. war against Iran.

South Korea’s military said in a statement the ongoing drills with the U.S. would end Friday, not Aug. 27 as initially planned. It said the allies also agreed to downsize some joint field training exercises.

The statement said South Korea and the U.S. will discuss and carry out various steps to achieve objectives of their drills and establish combined defense postures.

Many experts say Trump’s move threatens to hurt combined U.S.-South Korean defense posture and eventually weaken their decades-long alliance.

Ulchi Freedom Shield is largely a computer-simulated command post exercise meant to hone the allies’ ability to deal with potential North Korean aggression. The two countries usually hold field a set of training exercises during the command post exercise period.

The drills and a similar springtime exercise are a central pillar of the U.S.-South Korea alliance, which dates to the 1950-53 Korean War. But it’s also a long-running source of tensions with North Korea, which has denounced the exercises as a rehearsal for an invasion.