WASHINGTON — President Donald Trump ordered the Pentagon on Sunday to scale back planned joint military exercises with South Korea after the Republican president said it declined to help denuclearize Iran.

Trump said in a social media post that the exercises slated to begin this week are costly and “send a signal that is totally inappropriate and hostile” to North Korea, which he said “has been unthreatening and respectful” while Trump has been in the White House.

“Therefore, and based on the fact that it is too late to cancel, I have instructed Secretary of War, Pete Hegseth, to substantially reduce the Joint Military Exercises!” Trump wrote. Trump added that he recently asked South Korea’s president to join the U.S. in its efforts to denuclearize Iran, “and they said, ‘No thanks!’”

The 11 days of exercises involving 18,000 South Korean soldiers were designed to beef up readiness against North Korean threats.

North Korea on Friday threatened unspecified stern steps against the U.S. and South Korea, describing their military drills as a “a rehearsal for an aggressive war” that are triggering greater instability in the region.

The warning was typical of the harsh rhetoric that North Korea often deploys ahead of major U.S.-South Korean military exercises. Experts say North Korea has often used its rivals’ drills as a pretext to ramp up testing activities to expand its weapons arsenals and promote public support for leader Kim Jong Un.

U.S. and South Korean forces were expected to practice joint operations in complex scenarios, including a live-fire exercise to test joint precision targeting and maneuver, a wet gap crossing, and distribution of prepositioned military equipment, according to the U.S. military.

The U.S. military has said the exercise “reinforces the role of the alliance as the linchpin for regional peace and security” and reaffirms “the ironclad commitment between the United States and the Republic of Korea to defend their homelands.”

Trump met with the reclusive North Korean leader three times during his first term to discuss the country’s nuclear program, most recently in 2019. Since returning to office, Trump has expressed interest in continuing those discussions.

Trump’s announcement came a day after he posted a photo of himself standing next to North Korea’s Kim, writing that the two leaders get along great “despite the unfriendly look on this particular picture.”

This is not the first time that Trump has sought to end the exercises. During his first term he also issued a surprise announcement that called the wargames “provocative.”

“We will be stopping the war games, which will save us a tremendous amount of money, unless and until we see the future negotiation is not going along like it should,” Trump told reporters after his 2018 meeting with Kim Jong Un in Singapore.