Trump and Kim said they "commit to recovering" the remains of US service members killed in the war of 1950-1953, "including the immediate repatriation of those already identified."

The issue's inclusion at the summit reflects the efforts of fierce lobbying by veterans groups in America, including Veterans of Foreign Wars, which wrote to Trump last week asking him to discuss the matter with Kim.

"As the leader of the free world, we urge you to do everything in your power to ensure that those who paid the ultimate price for freedom during the Korean War are finally returned home," VFW head Keith Harman wrote.

More than 35,000 Americans were killed on the Korean peninsula during the war, with 7,700 of these US troops still listed as missing in action -- most of them in North Korea.

According to VFW, an agreement between the US and North Korea spanning 1990 to 2005 saw the return of 229 sets of remains, with many more identified.

But the program was suspended as political conditions deteriorated between the two countries.

After the summit, Trump said the process of repatriating remains would begin immediately.

"So many people have talked to me about it," Trump told reporters.

"I brought it up at the very end. And (Kim) was really very gracious. Instead of saying, 'Well, let's talk about it the next time,' he said, 'It makes sense. We will do it.'"

In a statement, Harman said he "salutes" Trump for bringing the issue to the table, and thanked Kim.

"We must have hope that this agreement will finally bring peace to the peninsula and help bring closure to thousands of families of missing American servicemen from the Korean War," Harman said.

"Now the hard work to bring the initiative to fruition begins."