President Donald Trump says he may be meeting with North Korea's Kim Jong Un on Sunday during a visit to the demilitarised zone with South Korea.

Mr Trump offered the update during a press conference as he wraps up his appearance at the Group of 20 summit in Japan hours after tweeting his invitation.

Mr Trump says Kim has responded to the offer and was "very receptive" to the idea. He says: "We may be meeting with Chairman Kim... we'll find out."

It is unclear whether Mr Trump was referring to a private communication or public comments from Choe Son Hui, North's First Vice Foreign Minister, who called the prospect of a meeting a "very interesting suggestion."

Eyeing a history-making photo opportunity, President Trump issued a Twitter invitation to North Korea's Kim Jong Un to join him for a hand shake during a visit by Trump to the demilitarized zone with South Korea.

The invitation, while long rumored in diplomatic circles, still struck as an impulsive display of showmanship by a president bent on obtaining a legacy-defining nuclear accord. Presidential visits to the DMZ are traditionally treated as carefully guarded secrets for security reasons, for one.

He told reporters during a breakfast with Saudi Arabian Crown Prince Mohammed bin Salman that he would be visiting the heavily fortified area between the two Koreas.