President Donald Trump said Thursday that the summit scheduled with North Korean leader Kim Jong-un for June 12 in Singapore has been cancelled.

"The Singapore summit, for the good of both parties, but to the detriment of the world, will not take place," Trump said in a letter addressed to the North Korean leader.

The U.S. president warned Kim about making military threats.

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

The U.S. president added that "the world, and North Korea in particular, has lost a great opportunity for lasting peace and great prosperity and wealth. This missed opportunity is a truly sad moment in history."

The suspension of the Trump-Kim meeting follows days of rising tensions and uncertainty about the summit.

North Korea said Thursday that the summit's future was "entirely dependent" upon Washington, after both countries threatened to cancel or delay the historic meeting.

"Whether the U.S. will meet us at a meeting room or encounter us at nuclear-to-nuclear showdown is entirely dependent upon the decision and behavior of the United States," Choe Son-hui, a North Korean deputy foreign minister, said.

Last week, Pyongyang threatened to pull out of the summit due to the White House's pressure to impose a "unilateral" denuclearization model, while Trump had spoken on Tuesday of a possible postponement.

The Singapore summit would have been the first meeting between a U.S. president and a North Korean leader in the almost seven decades since the 1950-1953 Korean War.