“I feel it is inappropriate, at this time, to have this long-planned meeting,” Trump wrote in a letter to Kim that was released by the White House.
Speaking later at the White House, Trump said his “maximum pressure campaign” against North Korea would continue and threatened a military response if Kim resumes nuclear activity.
But he also left the door open for the talks to take place if Kim takes “constructive” steps toward peace.
“It’s possible that the existing summit could take place, or a summit at some later date,” Trump said during a bill signing ceremony.
The two were scheduled to meet June 12 in Singapore in what would have been the first meeting between a sitting U.S. president and a North Korean leader.
The sudden cancellation is a major setback for Trump, who made nuclear diplomacy with Pyongyang his top foreign policy goal. The president was eager to have the meeting, openly musing about how brokering an agreement with Kim could earn him a Nobel Peace Prize.