President of United States of America has announced to cancel his planned summit with the North Korean leader, Kim Jong-un, blaming his decision on a threatening statement from the Pyongyang regime in a formal letter to Kim released by the White House on Thursday, scrapping plans for what would have been a historic diplomatic summit.

"I was very much looking forward to being there with you. Sadly, based on the tremendous anger and open hostility displayed in your most recent statement, I feel it is inappropriate, at this time, to have this long-planned meeting," Trump wrote. "Therefore, please let this letter serve to represent that the Singapore summit, for the good of both parties, but to the detriment of the world, will not take place."

Trump and Kim were scheduled to meet in Singapore on June 12, for what would have been the first face-to-face meeting between a US and North Korean leader.

The decision ends months of diplomatic advances between the US and North Korea that Trump repeatedly heralded as the likely precursor to a historic peace deal and the denuclearization of North Korea. Now, the détente between Washington and Pyongyang appears in jeopardy, with a return to the bellicose rhetoric that has defined the US-North Korea relationship for much of Trump's presidency once again peering over the horizon.

Although much of the tone of the letter was regretful and it contained conciliatory passages, it included a reminder of the size of the US nuclear arsenal.

“You talk about your nuclear capabilities, but ours are so massive that I pray to God they will never have to be used,” Trump wrote.

The cancellation came two days after a visit to the White House by the South Korean president, Moon Jae-in, who had sounded hopeful about a historic summit that he portrayed as vital to peace on the Korean peninsula.

Moon held an emergency meeting with top officials just before midnight local time on Thursday. His office appeared surprised by the announcement, with spokesman Kim Eui-kyeom saying: “We are trying to figure out what President Trump’s intention is and the exact meaning of it.”

Pyongyang also appeared to be taken entirely by surprise.

“There was a real sense of shock amongst the people I was sitting with, the North Korean officials,” Will Ripley, a CNN reporter, said shortly after he read Trump’s letter to them.

Speaking in Geneva, the UN secretary general, António Guterres, said he was “deeply concerned” about the cancellation of the summit, and appealed for a continued dialogue to “find a path to the peaceful and verifiable denuclearization of the Korean peninsula”.

The immediate trigger for the row that erupted between Washington and Pyongyang and derailed the summit was the Trump administration’s repeated references to the “Libyan model”, which was presented by some officials as referring to Muammar Gaddafi’s 2003 agreement to abandon his nuclear weapons programme and surrender related equipment and materials to the US.

North Korea analysts said there were deeper problems underlying the proposed summit than heavy-handed use of menacing language.

 “Expectations were overblown for the North Korea summit, and there are legitimate reasons to question whether Kim Jong-un is serious about giving up its nuclear weapons, but Trump’s letter is an overreaction and ignores the role that top officials played in provoking this crisis,” Kelsey Davenport, director for nonproliferation policy at the Arms Control Association, said to Guardian.

With inputs from Guardian, CNN and BBC.