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.