Updated: May 23, 2018 4:49 AM ET | Originally published: May 22, 2018 12:48 PM EDT

South Korean President Moon Jae-in is in Washington Tuesday for a series of meetings with President Trump regarding the upcoming U.S. summit with North Korea – which could be in jeopardy following tough new rhetoric from Pyongyang and a new acknowledgement from Trump.

Speaking to reporters in the Oval Office, Trump said there was a “substantial” chance the summit “may not work out” for June 12, but that a decision would be reached soon. “We’re moving along. We’ll see what happens,” he said. “If it doesn’t happen, maybe it will happen later.”

Trump did not specify the conditions upon which the meeting would be predicated. The meeting between Trump and Moon came one week after North Korea suspended a meeting with South Korea over a joint military exercise with the United States, and threatened to cancel the summit with the U.S. South Korea has been instrumental in urging the two sides to come together.

President Moon arrived with his wife to Washington on Monday. He and Trump are scheduled for a meeting and a working lunch before he departs.

According to the South Korean Yonhap News Agency, President Moon’s national security adviser, Mr. Chung Eui-yong, told reporters en route to Washington that South Korea believes there is a “99.9 percent chance” the summit will still happen, but they are preparing themselves for a range of possibilities. The comments came before President Trump’s oval office remarks, but reveal how the U.S. and South Korea could be on different wavelengths when it comes to the summit. The meetings today, Chung explained, will be “candid discussions on how to make the North-U.S. summit a success and produce significant agreements and how to best implement those agreements.”

An official with the South Korean embassy, characterized the meeting between Trump and Moon as “an official working visit to exchange and discuss the two presidents’ thoughts and visions on the upcoming US-North Korea Summit,” according to a report from Yonhap The official also said Trump and Moon could discuss the U.S. forces deployed to South Korea, a point of contention because Trump wants to reduce the number stationed there.

During the meeting in the Oval Office, Moon told reporters he was confident in Trump’s peacemaking abilities, and that he the potential to bring prosperity to North Korea.

Trump also floated the idea of unifying North and South Korea. “Maybe in the future they will go back to one Korea,” he said.
North Korea said last week that it was considering cancelling the summit with the United States because it felt the U.S. was manipulating them into completely abandoning its nuclear weapon program. “We are no longer interested in a negotiation that will be all about driving us into a corner and making a one-sided demand for us to give up our nukes,” Kim Kye Gwan, North Korea’s first vice foreign minister, said in a statement, according to the Associated Press.

The statement came after Trump’s new National Security Adviser, John Bolton, compared the situation with North Korea to Libya, whose leader, Moammar Gadhafi agreed to abandon the country’s nuclear weapons program in 2003 exchange for sanctions relief. Eight years later, Gadhafi was overthrown during the Arab Spring in 2011, which undoubtedly sparked fear in North Korean leader Kim Jong Un.

In the Oval Office on Tuesday, Trump said Kim would be “very happy” if the negotiations came to fruition.

A former North Korean official who defected to South Korea told TIME that members of the North Korean government orchestrating the summit want Bolton off the negotiating team. And the New York Times reported that Trump is increasingly doubting the benefits of meeting with Kim Jong Un following his most recent rhetoric, although Chung, Moon’s national security adviser, said he was unaware of those feelings.

“During phone calls between our two leaders or talks between our National Security Councils, I never got such an impression,” he told reporters, according to Yonhap.

– With reporting by Charlie Campbell/Beijing

Write to Alana Abramson at Alana.Abramson@time.com.

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