And when North Korea dismantled its nuclear testing site Thursday, just hours before Trump pulled out of the summit, US officials said Kim had reneged on a pledge to allow worldwide observers to verify its destruction.
Mattis called the recent back-and-forth between President Donald Trump and North Korea, which seemed to indicate the summit would not happen as planned on June 12, the "usual give and take". Beijing had backed the summit and was possibly taken unawares with the cancellation following heated exchanges between Washington and Pyongyang this week. He told reporters Friday that "everybody plays games". "The North Koreans did not tell us anything - they simply stood us up", said the official, speaking on condition of anonymity.
Trump described the cancellation of the summit as "a tremendous setback" for North Korea and warned that the United States military is ready to act should Pyongyang take any "foolish and reckless" action.
"Under the current circumstances we hope both the DPRK and the United States can cherish the recent positive progress, stay patient, show goodwill, move in the same direction and continue to stay committed to promoting the denuclearisation of the peninsula", he added.
The North Korean regime rejected responsibility for the summit cancellation in a statement released by the state-run Korean Central News Agency (KCNA) on Thursday and attributed to Vice Foreign Minister Kim Kye Gwan, translated and quoted in 38 North, a web journal that provides analysis and insight into North Korea.
But it also followed escalating frustration - and newly antagonistic rhetoric - from North Korea over comments from Trump aides about US expectations for the North's "denuclearization".
Shortly before this, Mr Trump welcomed North Korea's willingness to hold talks "at any time", describing it as "warm and productive".
At a late afternoon briefing Thursday, a senior administration official described the recent interactions between the US and North Korea as "a trail of broken promises".
Both the meetings, he said, laid the ground work for a meeting between Kim and US President Donald Trump.
Several Western journalists were at the Punggye-ri test site in North Korea, pictured here via satellite, to witness its destruction.
North Korea later said it was willing to talk "at any time in any form".
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Robert Kelly, a professor of political science at South Korea's Pusan National University, told CNN earlier this week that "the Trump administration is going into [the summit] very, very quickly".
On Friday North Korea issued its response to Trump's cancelation of the summit, flipping back to language suggesting it fell victim to the whims of a madman. That was far different from his letter Thursday to North Korea leader Kim Jong Un, blaming "tremendous anger and open hostility" by Pyongyang for the US withdrawal.
One day after calling off a June 12 meeting between himself and Kim Jong Un, Trump takes a more conciliatory tone. "It could even be the twelfth", he said.
He was not informed of the decision before Mr Trump's announcement, reports said.
He added that North Korea "inwardly highly appreciated" Trump for agreeing to the summit, and hoped the "Trump formula" would help lead to a deal between the adversaries.
He said the North Koreans remain "unchanged in our goal" of peace and stability and were willing to "offer the USA side time and opportunity".
The decision blindsided treaty ally South Korea, which until now had brokered a remarkable detente between Washington and Pyongyang.
A senior White House official said Pyongyang had demonstrated a "profound lack of good faith" in the run-up to the summit - including standing up the White House's deputy chief of staff, who had travelled to Singapore for preparatory talks.
The explosions, that were witnessed by invited global media, were supposed to build confidence ahead of the planned meeting next month between Kim and President Donald Trump.
But many felt the Trump administration was rushing into a summit too quickly, with insufficient preparation.