President Donald Trump has said the US will “substantially reduce” joint military exercises with South Korea, citing his “very good relationship” with North Korea’s leader Kim Jong Un.

“These exercises are not only costly, with much of these costs paid for by the United States of America (as usual!), but send a signal that is totally inappropriate and hostile,” Trump wrote on Truth Social on Sunday.

He also noted that South Korea had recently declined to join the US in the “denuclearisation” of Iran.

The decision comes after Pyongyang this month conducted ballistic missile tests that are banned by the United Nations.

Trump said in his social media post that it was “too late to cancel”, as the US and South Korea were due to start their annual military exercises on Monday.

He added: “While somewhat unrelated (?), I recently asked the President of South Korea if they would like to join us in the Denuclearization of the Islamic Republic of Iran, and they said, ‘No thanks!'”

Last week, US and South Korean military leaders held a joint press conference announcing Ulchi Freedom Shield.

They said the 11-day event would be similar in scale to previous years, with about 18,000 South Korean soldiers participating.

During the news conference, military leaders also mentioned North Korea’s deployment of troops to aid Russia’s war against Ukraine.

US military spokesperson Ryan Donald said “our training accounts for that threat”, referring to North Korean soldiers returning from the battlefield.

North Korea’s foreign ministry commented on the joint drills on Friday, reiterating its rejection of any threat or challenge by exercising its right to self-defence.

The joint exercises come days after South Korea, the US and Japan detected the second North Korean missile test in days.

Pyongyang has accelerated efforts to expand its nuclear and missile programmes since the collapse in 2019 of Kim’s high-profile diplomacy with Trump during his first term in the White House.

He became the first ever sitting US president to set foot in North Korea when he visited seven years ago.