Washington and Seoul are security allies, with around 30,000 US troops stationed in the South to defend it from its neighbour, which invaded in 1950.

They hold joint military exercises every year that infuriate Pyongyang, which has long demanded an end to the drills and often responds with actions of its own, ratcheting up tensions.

"We will be stopping the war games which will save us a tremendous amount of money," Trump told reporters.

"I think it's very provocative," he said -- echoing Pyongyang's traditional line.

"Under the circumstances we are negotiating a complete deal," he added. "It is inappropriate to have war games. Number one, we save money. A lot. Number two, it is really something they very much appreciated."

The move, if fulfilled, would appear to be effectively an implementation of the "freeze for freeze" proposal promoted by China, under which the North would stop nuclear and missile tests in exchange for a halt to the exercises.

Kim has previously declared a moratorium on testing, saying that the development of his nuclear arsenal is complete.

Trump also said he wanted to withdraw the US troops stationed in the South, something he promised on the campaign trail, saying: "I'd like to be able to bring them back home."

The issue was "not part of the equation right now", he said, but "at some point I hope it will be."

Trump's declarations are likely to alarm conservatives in South Korea, who have appealed to him not to put their country's security at risk.