The motorcade traveled to Beijing's airport, where the limousine entered the charter flight terminal.
"And I understand. that they've already sent back or are in the process of sending back the remains of our great heroes who died in North Korea during the war", Trump said at a Cabinet meeting.
Moon's office said he made the remarks to Russian media ahead of his trip to Moscow later this week.
Secretary of State Mike Pompeo reportedly shared a mutual laugh with North Korean leader Kim Jong Un on their first meeting that he would go on to describe as a success - despite joking that he was trying to kill Kim.
The officials, speaking on condition of anonymity, said North Korea would hand over the remains to United Nations Command in South Korea, and they would then be transferred to Hickam Air Force Base in Hawaii.
China and the USA both hope to see the Korean peninsula free of nuclear weapons, but Beijing is concerned Washington and Pyongyang might move closer at its expense, a possibility that China sees as threatening to its economic and security interests in the region. -South Korean military exercises.
Denmark, who left the Defense Department in 2017 and is now director of the Asia Program at the Woodrow Wilson International Center for Scholars, said he has yet to see any indication that Kim wants to pursue denuclearization or disarmament, and instead appears to be exclusively interested in engaging the world as a nuclear power.
Last week, President Trump told Fox News that North Korea will begin turning over remains to the US following his summit meeting with dictator Kim Jong Un.
Mr Kim also told Mr Xi he was willing to bolster the bilateral friendship and co-operation, it said.
President Donald Trump raised the likelihood of the repatriation of remains last week, in the wake of his meeting with North Korean leader Kim Jong Un.
The US President also agreed to stop "war games", joint military drills between the US and South Korea that the North has opposed to as "provocative".
Following the meeting, Kim toured China's an agricultural technology park and rail traffic control centre in Beijing, Xinhua said, in a possible hint at some of the North's goals for future economic cooperation with China. Recent threats by President Trump on trade that aggravate and harm U.S.
That could allow the lifting of UN Security Council economic sanctions that have caused a plunge in North Korea's foreign trade, although the USA insists that easing of sanctions can only come after the North shows it has ended its nuclear programs.