NORTH Korea handed over 55 boxes carrying remains thought to be of US soldiers killed in the 1950-53 Korean War on Friday, officials said.

It is the first step in implementing an agreement reached in a landmark summit between the two counties in June.

The handover of the boxes represents a modest diplomatic triumph for US President Donald Trump from his June 12 summit with North Korean leader Kim Jong-un in Singapore.

“At this moment a plane is carrying the remains of some great fallen heroes from America back from the Korean War,” Mr Trump said at an event at the White House.

“I want to thank Chairman Kim for keeping his word. We have many others coming. But I want to thank Chairman Kim in front of the media for fulfilling a promise that he made to me.

“And I’m sure that he will continue to fulfil that promise as they search and search and search,” Mr Trump said.

The transfer of the remains coincided with the 65th anniversary of the 1953 armistice that ended fighting between North Korean and Chinese forces and South Korean and US-led forces under the UN Command.

The two sides remain technically at war because a peace treaty was never signed. More than 7,700 US troops who fought in the Korean War remain unaccounted for, with about 5,300 of those lost in what is now North Korea.

The pledge to transfer war remains was seen as a goodwill gesture by Kim at the summit and will rekindle hopes for progress in nuclear talks, which so far has appeared scant.

In a statement on the remains handover, the White House said it was “encouraged by North Korea’s actions and the momentum for positive change,” while South Korea called it “meaningful progress that could contribute to fostering trust” between Pyongyang and Washington.

A US military transport plane flew to an airfield in North Korea’s northeastern city of Wonsan to bring the remains to Osan air base in South Korea. At Osan, soldiers in dress uniforms with white gloves slowly carried the 55 cases to vans waiting on the tarmac.

The UN Command said the remains would be flown to Hawaii for further processing. Defence Secretary Jim Mattis said on Friday that the US military was “absolutely” considering the possibility of sending personnel to North Korea for this purpose, adding the handover set a positive tone for broader diplomatic negotiations.