"There were no surprises, they had spoken on all of these issues in advance", Dana White, the chief Pentagon spokesperson, told ABC News when asked if Mattis knew about the president's announcement.
On Monday evening, Pompeo said that the US' "ultimate objective" remains the complete denuclearisation of the Korean Peninsula, and that Washington is willing to provide "unique security assurances" if Pyongyang agrees to do so.
Tuesday morning saw the South Korean President tell a cabinet meeting he "could hardly sleep last night" because of the Trump-Kim summit.
China was not a direct party to the summit but Mr Kim met President Xi Jinping twice in the run-up, and even borrowed an Air China 747 to get to Singapore.
China, North Korea's most important economic and diplomatic supporter despite its anger at Pyongyang's nuclear and missile tests, wasted little time with a reminder that United Nations sanctions could be adjusted.
Speaking at a press conference following the summit, Trump said: "Now we can have hope that [the war] will soon end and it will, it will soon end". "Trump delivered it while getting nothing in return beyond the same generalities that North Korea has been offering since the early 1990s". But we'll be saving a tremendous amount of money.
At the same time, he noted that the U.S. forces' deployment in South Korea had not been discussed with Kin Jong Un.
"We hope that the outcomes of the US-DPRK Summit will be implemented, thus paving the way for lasting peace and stability in the Korean Peninsula", the ministry said.
Fox News host calls Trump a 'dictator'
But the daughter of US Ambassador to Russia Jon Huntsman later apologised on air for what she had said . Donald Trump arrived in Singapore directly from Quebec, Canada after attending G7 summit on Sunday.
Yesterday, the two leaders signed a commitment towards denuclearisation of the Korean Peninsula. Representative Ed Royce of California, chairman of the House Foreign Affairs Committee, applauded Trump for pursuing peace through diplomacy, but also said Kim had "gained much" on Tuesday, "including an apparent promise" from Trump to suspend military drills.
"Six months ago, most military and foreign policy analysts were predicting a bloody war on the Korean Peninsula". Under the circumstances we are negotiating a complete deal", Trump said, adding "It is inappropriate to have war games.
But Daniel Davis, a retired army lieutenant colonel and fellow at the Defense Priorities military think tank, said suspending the drills would have no short-term impact on US and South Korean military readiness. "South Korea joint military exercises".
If, as Trump said on Tuesday he sensed, Kim wants the grand bargain of disarmament for economic integration, the personal endorsement from the two leaders on negotiations may be all that counts.
President Trump and North Korean dictator Kim Jong Un walk together during their summit in Singapore.
North Korea is now the subject of sanctions imposed by the UN Security Council and, additionally, is impacted by unilateral restrictive measures by the US.
I just think that we are now we are going to start the process of denuclearization of North Korea, and I believe that he's going back and will start it virtually immediately, and he's already indicated that and you look at what he's done. "President Trump for the first time in 20 or 30 years of diplomatic negotiations with North Korea began to take this kind of political approach and try to tackle the root cause of this problem, which is high levels of mutual distrust".