US President Donald Trump said on Wednesday that he will not meet with top leader of the Democratic People's Republic of Korea (DPRK) Kim Jong Un during his Asia trip this weekend.

"I'll be meeting with a lot of other people, not ... him," Trump told reporters at the White House before heading toward the Group of 20 (G20) summit in the Japanese city of Osaka slated on June 28-29.

"But I may be speaking with him in a different form," he said, without elaboration.

Trump's words came after South Korean President Moon Jae-in revealed on Tuesday that US and DPRK officials were holding backdoor talks to arrange a third meeting between the leaders of the two countries.

Trump will make a two-day visit to South Korea after attending the G20 summit.

Trump and Kim have exchanged letters recently, which has been seen as a signal for an improving relationship.

The denuclearization negotiations between Pyongyang and Washington have stalled since the second summit between Kim and Trump ended with no agreement in February in the Vietnamese capital of Hanoi.