UNITED STATES President Donald Trump ordered the Pentagon to scale back annual joint military exercises with South Korea, saying the ally declined to help with the war against Iran and citing his good relationship with North Korea’s Kim Jong Un.

Mr Trump said in a social media post that the exercises, which began today, are not only costly but “send a signal that is totally inappropriate and hostile” to North Korea, which he said “has been unthreatening and respectful” during his time 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!” Mr Trump wrote. 

The increasingly erratic president added that he recently asked South Korea’s president if they would join the US in the “denuclearisation” of Iran, “and they said: ‘No thanks!’”

The move is a sharp turnaround from how his administration has viewed South Korea in recent months.

In May, Mr Hegseth praised the long-time ally for its commitment to increase defence spending and its “leadership in assuming primary responsibility for the security of the Korean Peninsula” during a meeting at the Pentagon.

“It demonstrates alliance burden-sharing that all of America’s partners would do well to follow,” the defence secretary added.