WASHINGTON (KYODO) - US President Donald Trump said on Friday (Aug 9) that North Korean leader Kim Jong Un has expressed displeasure about joint military exercises that are under way between the United States and South Korea.

In what Trump called a "beautiful" three-page letter he received on Thursday, Kim said he does not like conducting the short-range ballistic missile tests North Korea has been doing in recent weeks, but justified the move as a response to the US-South Korea drills.

"He wasn't happy with the tests... the war games on the other side, with the United States," Trump told reporters at the White House.

The US leader also mentioned the possibility of another meeting with Kim.

"I think we'll have another meeting," he said, without referring to when such a meeting could take place.

Trump said the letter was hand-delivered, but did not say who delivered it.

Trump repeated his view that he "never liked" joint military exercises with South Korea.

"I've never been a fan. You know why? I don't like paying for it. We should be reimbursed for it," he said.

However, Trump said he likes the current drills - which started this week and will run through late August - because they are intended to test Seoul's capabilities to retake operational control from Washington during wartime.

"This was a turnover of various areas to South Korea. I like that because that's what should happen," he said.

In a June 30 meeting at the inter-Korean truce village of Panmunjeom, Trump and Kim agreed to restart working-level denuclearisation negotiations within weeks.

But such talks have yet to take place.

On Wednesday, US Secretary of State Mike Pompeo expressed hope that the two sides will resume stalled denuclearisation talks "in the coming weeks."