U.S. and North Korean officials met at the demilitarized zone Sunday to talk about a possible summit between President Donald Trump and North Korean leader Kim Jung Un.
After calling off the talks Thursday, Trump said the June 12 summit in Singapore may very well take place as scheduled.
"I truly believe North Korea has brilliant potential and will be a great economic and financial nation one day. Kim Jong Un agrees with me on this. It will happen," Trump tweeted Sunday.
"U.S. Ambassador to the Philippines, and former ambassador to South Korea, Sung Kim is leading the U.S. delegation at the preparation talks. Reports say the meetings are expected to last until Tuesday.
"We can be successful in the denuclearization of the Korean Peninsula, that would be a great thing for North Korea, it would be a great thing for South Korea, it would be great for Japan, it would be great for the world, it would be great for the United States, it would be great for China. A lot of people are working on it. It's moving along very nicely," Trump said.
It is not exactly clear what made Trump change his mind about wanting to meet with Kim just a day after he called off their talks.
Trump was angered over the North's insult of Vice President Mike Pence and its threat to use nuclear force. Pence remarked last week that North Korea could wind up like Libya -- a country mired in chaos since it gave up its nuclear ambitions and saw its longtime dictator killed.
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But Trump said Friday “everybody plays games,” and noted North Korea's "warm and productive" reaction to his letter to Kim, canceling their talks.
North Korean state media has reported on Kim's "fixed will" that a summit with Trump should go ahead.
South Korean President Moon Jae-in met Saturday with North Korean leader Kim near the two Koreas' heavily militarized border.
The leaders exchanged views on how to prepare for the North's possible summit with Trump, the South Korean presidential office said.
After the meeting, South Korea's President Moon was upbeat.
"It was like an ordinary encounter between friends," he said of his Saturday meeting with Kim Jong Un.
Moon said the North Korean leader remains committed to denuclearization.
"What's uncertain for Kim is not his intention to denuclearize, but the U.S. stance in hostile relations with North Korea and whether the U.S. can really secure and guarantee his regime," Moon said.
Kim thanked Moon "for much effort made by him" towards the summit, and said he hoped to improve relations with Washington and "establish mechanism for permanent and durable peace."
Leaders of North and South Korea also agreed to "meet frequently," the North's KCNA agency added.
White House correspondent Steve Herman contributed to this report.