Washington: President Donald Trump cancelled his planned summit with North Korean leader Kim Jong Un that had been scheduled for 12 June in Singapore, citing “tremendous anger and open hostility" in recent statements from Pyongyang.

Trump’s decision was communicated on Thursday in a letter to Kim released by the White House.

North Korea hardened its rhetoric toward the US earlier Thursday, warning it was ready for a “nuclear-to-nuclear" showdown if the US didn’t follow through on the summit.

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

With the summit abandoned — at least temporarily — the next steps are unclear. Trump has said that if the 12 June meeting were to fall through, the US would continue exerting maximum economic pressure on Kim and his regime.

The highly anticipated summit had been cast by the White House as an opportunity to stave off a military conflict with North Korea and showcase Trump’s ability to make progress where his predecessors had struggled.

But Trump ultimately ran into the same diplomatic quandary that has flummoxed US presidents for the past 25 years: the inability to persuade a stubborn regime to give up a nuclear program that it regards as key to its survival.

Trump agreed to meet Kim after the two leaders spent most of 2017 exchanging increasingly hostile and bellicose barbs. Seoul led the effort at detente with Pyongyang that led to the two countries competing together at the Winter Olympics.