WASHINGTON — President Trump said on Tuesday that his planned summit meeting next month with North Korea’s leader, Kim Jong-un, might be delayed.
“There’s a very substantial chance that it won’t work out,” Mr. Trump told reporters before a meeting in the Oval Office with South Korea’s president, Moon Jae-in. “It may not work out for June 12.”
Mr. Trump expressed continued enthusiasm for the diplomatic encounter, saying he believed it could usher in a period of prosperity for North Korea. But he acknowledged that recent statements by North Korea had cast a pall of uncertainty over the timing of the meeting, which is set for Singapore. He appeared as baffled as anyone else about what might come next.
“We’re moving along. We’ll see what happens,” Mr. Trump said. “There are certain conditions we want to happen. I think we’ll get those conditions. And if we don’t, we won’t have the meeting.
“If it doesn’t happen, maybe it will happen later,” he added. “Maybe it will happen at a different time. We will see. We are talking.”
The president said he detected a shift in Mr. Kim’s tone after the North Korean leader met for a second time with China’s president, Xi Jinping, several weeks ago. He suggested that Mr. Xi might be influencing North Korea’s approach to the United States.
“There was a different attitude by the North Korean folks after that meeting,” Mr. Trump said. “I can’t say that I’m happy about it.”
Mr. Trump’s comments came in a lengthy exchange with reporters, in which the president invited Mr. Moon to offer his own views. He acknowledged the skepticism in the United States about the prospects for a successful negotiation, but said Mr. Trump’s participation set this process apart from previous ones.
“I have every confidence that President Trump will be able to achieve a historic feat,” Mr. Moon said through a translator. “I will spare no effort to provide necessary support.”
Mr. Moon has acted as a go-between for Mr. Trump and Mr. Kim. The American president is likely to seek reassurances from Mr. Moon that the diplomatic overture North Korea initiated in January will not end in failure.
Mr. Moon had his own history-making encounter with Mr. Kim last month, which buoyed hopes for the meeting between the North’s leader and Mr. Trump. But last week, the North Koreans said they were having second thoughts, objecting to the Trump administration’s demand that they relinquish their nuclear weapons before receiving any benefits.
Mr. Moon has taken the lead role in orchestrating the diplomacy that led to the Trump-Kim summit. South Korean officials conveyed the invitation from Mr. Kim to Mr. Trump to meet, which the president accepted on the spot, surprising his visitors as well as his own advisers.
Mr. Trump spoke to Mr. Moon by phone on Saturday, suggesting the depth of uncertainty he feels about the change in tone from Pyongyang. North Korea objected particularly to John R. Bolton, the new national security adviser, who said he viewed Libya as a template for negotiating with North Korea.
Mr. Trump subsequently disavowed Mr. Bolton’s remarks, acknowledging that Libya’s voluntary disarmament in 2003 did nothing to protect its leader, Col. Muammar el-Qaddafi, from being killed by his own people in the Arab upheavals less than a decade later.
Speaking last week, the president offered assurances to Mr. Kim that if he agreed to give up his nuclear arsenal, he would survive in power and his people would prosper. But the tone in North Korea’s media has remained suspicious and grudging.
Mr. Moon will likely seek assurances of his own — not least that the United States will maintain American troop levels in South Korea, regardless of its negotiation with Mr. Kim. Mr. Trump has long expressed a desire to withdraw troops, and the National Security Council has asked the Pentagon to prepare options for changing levels of military forces.
Still, South Korean officials said Mr. Moon would deliver an essentially upbeat message to Mr. Trump.
“We believe there is a 99.9 percent chance the North Korea-U.S. summit will be held as scheduled,” Mr. Moon’s national security adviser, Chung Eui-yong, said to reporters traveling to Washington. “But we’re just preparing for many different possibilities.”
Mr. Chung said the two leaders would have “candid discussions on how to make the North-U.S. summit a success and produce significant agreements and how to best implement those agreements.” He insisted that Washington and Seoul were closely coordinating their efforts.
Experts in South Korea said there was still considerable hope for the Trump-Kim meeting, and that the White House should not get rattled.
“There may be a sense here that the Trump team is overreacting to North Korea’s pushback last week and losing sight of the big picture,” said John Delury, an associate professor of Chinese studies at Yonsei University in South Korea.
“Of course gaps remain in terms of negotiating peace and denuclearization of the Korean Peninsula.” Mr. Delury said. “That’s the reason a negotiation is necessary.”