US President Donald Trump has instructed the Pentagon to “substantially reduce” 10 days of joint military exercises with South Korea as they were about to get underway, citing the cost of the drills and Seoul’s refusal to take part in actions against Iran, Reuters reports.

Hours before exercises were scheduled to begin, Trump said on his Truth Social site that although it was too late to cancel the drills entirely, he was “not happy” that the US had previously agreed to participate and highlighted his “very good relationship” with North Korean leader Kim Jong Un.

“These exercises are not only costly… but send a signal that is totally inappropriate and hostile, to a Country that, as long as Donald J. Trump has been President, has been unthreatening and respectful,” Trump wrote.