WASHINGTON — President Trump said on Friday that he had asked Secretary of State Mike Pompeo to skip a planned trip to North Korea, abruptly canceling the next round of negotiations on the country’s nuclear program in his first public acknowledgment that his diplomatic overture to the North Korean leader, Kim Jong-un, had run into trouble.

“I feel we are not making sufficient progress with respect to the denuclearization of the Korean Peninsula,” Mr. Trump said in a series of Twitter posts on Friday. “In the meantime I would like to send my warmest regards and respect to Chairman Kim. I look forward to seeing him soon!”

Mr. Pompeo and his newly appointed special envoy were scheduled to travel to North Korea next week to continue denuclearization talks.

In his tweets on Friday afternoon, Mr. Trump said the nuclear negotiations had been hampered by a lack of support from China, which he attributed to its increasingly rancorous trade dispute with the United States.

“Secretary Pompeo looks forward to going to North Korea in the near future, most likely after our Trading relationship with China is resolved,” he said.

But lower-level trade negotiations between Washington and Beijing ended on Thursday with few signs of progress, raising the odds of additional American tariffs on Chinese goods. Mr. Trump also met with legislators to discuss a new law aimed at curbing Chinese investment.

With many analysts expecting the relationship with China to get worse before it gets better, Mr. Trump has set a high bar for resuming high-level negotiations with North Korea. At the same time, he left the door open to a meeting between himself and Mr. Kim — the kind of encounter that the president could use to break a deadlock.

Mr. Trump’s announcement was a blow to Mr. Pompeo, who only a day earlier announced the appointment of an automotive executive as special envoy for North Korea. The envoy, Stephen E. Biegun, was scheduled to accompany Mr. Pompeo to Pyongyang.

In South Korea earlier this month, President Moon Jae-in outlined plans for broad economic cooperation with the North, including joint economic zones on the border and a rail network. Mr. Moon also said he would open a diplomatic “liaison office” in North Korea this year.

Mr. Moon turned aside concerns from the conservative political opposition that his government was moving too quickly in its overtures to the North, which has yet to begin dismantling its nuclear weapons program, and creating a potential rift with Washington.

In a speech, Mr. Moon said that South Korea should not take a back seat in resolving disputes between the North and the Trump administration.

“It is important to recognize that we are the protagonists in Korean Peninsula-related issues,” he said. “Developments in inter-Korean relations are not the by-effects of progress in the relationship between the North and the United States.”