His statement was quickly portrayed by critics as a major, unreciprocated concession to a country that only past year was threatening Seoul and Washington with nuclear war.
"Look, president Trump is a deal-maker", he said.
In China, Chinese Foreign Minister Wang Yi told reporters that the fact that the two leaders "can sit together and have equal talks has important and positive meaning, and is creating a new history". The South Korean military seemed similarly surprised. "Plus, I think it's very provocative".
In an exclusive interview with ABC News's George Stephanopoulos and at a press briefing Trump announced that he was suspending military exercises conducted annually in South Korea by the US military. "So, for the thousands and thousands, I guess way over 6,000 that we know of in terms of the remains, they'll be brought back".
"That was a very last-minute", Trump said at a news conference, adding, "the remains will be coming back". I expect he has experts that know about the issues to give him good advice and I hope the president kind goes into it slowly. "But we'll be saving a tremendous amount of money".
Only hours before the summit, Mattis told Pentagon reporters that, as far as he knew, the issue of USA troops in South Korea would not be part of any discussion in Singapore.
The Australian government has cast doubt over whether Donald Trump has suspended military exercises with South Korea, noting that was not part of the joint declaration between the United States and North Korea.
"I offer my heartfelt congratulations and welcome the success of the historic North Korea-United States summit", Moon said in a statement. The former reality-TV star seemed to turn a blind eye to the perceived human rights violations committed in the isolated authoritarian state, including "an nearly complete denial of the right to freedom of thought, conscience and religion" and the use of prison labor camps, deliberate starvation, executions, and other methods of torture to deter dissent, according to a 2014 United Nations report.
A spokeswoman for US military forces in Korea said they had not received any direction to cease joint military drills.
There are also annual springtime drills.
Japan would continue joint military exercises with the U.S. and would stick to plans to bolster its defences against a possible ballistic missile strike from North Korea. North Korea has traditionally responded to them angrily, while the governments in Seoul and Washington have said they are defensive in nature and part of the "ironclad" U.S. South Korea contributes, but not 100 percent, which is a subject that we have to talk to them about also.
"If our alliances are getting weaker and we're not going to do military exercises, where is the pressure?" said Michael Green, senior vice president for Asia and Japan Chair at the Center for Strategic and International Studies (CSIS), during a phone briefing.