WASHINGTON (Yonhap) -- US President Donald Trump on Friday put a summit with North Korean leader Kim Jong-un back on for June 12 following weeks of uncertainty over whether it would take place.

Trump said after meeting with a senior North Korean official at the White House that the summit will go ahead in Singapore to discuss the dismantlement of the North's nuclear weapons program.

"We'll be meeting on June 12th in Singapore," Trump told reporters on the White House grounds after seeing off Kim Yong-chol, a close aide to the North Korean leader.

"And I think it'll be a process. I never said it goes in one meeting. I think it's going to be a process. But the relationships are building, and that's a great positive."

The two sides have been at odds over how far North Korea will go to dismantle its nuclear weapons program and what security guarantees the regime would receive in return.

The US wants to see the North quickly and "irreversibly" dismantle the program before providing significant concessions, but the North has rejected "unilateral" abandonment.

"I think they want to do that. I know they want to do that," Trump said when asked if North Korea is serious about denuclearizing.

"They want other things along the line. They want to develop as a country. That's going to happen, I have no doubt."

Still, he refused to say whether the North agreed to the US demand for complete, verifiable and irreversible denuclearization.

"We talked about a lot of things. We really did," he said. "But the big deal will be on June 12th. And again it's a process ... we're not going to go in and sign something on June 12th, and we never were. We're going to start a process."

The US president said he told the North Korean delegation that they could take their time.

"We can go fast. We can go slowly. But I think they'd like to see something happen, and if we can work that out, that'd be great," he said.

Kim Yong-chol, the top North Korean to enter the White House in nearly two decades, traveled from New York following two days of meetings with US Secretary of State Mike Pompeo on a possible summit between their leaders.

Pompeo said after the meetings that "real progress" was made toward "setting the conditions" for a summit, but he also said there remains "a great deal of work to do."

The US president said the North Korean official handed him a "very nice" and "very interesting" letter from Kim, but later added that he hadn't opened it.

"I didn't open it in front of the director," Trump said.

"I said, 'Would you want me to open it?' He said, 'You can read it later.' I may be in for a big surprise, folks."

Trump called off the summit in an open letter to Kim last week, citing "open hostility" from the regime. Following a conciliatory statement from the North, he put the summit back on track, and officials from both sides have been continuing meetings on the inter-Korean border as well as in Singapore to hammer out the substantive and logistical details.

On Friday Trump said he doesn't want to use the term "maximum pressure" anymore, a term his administration has coined to describe its sanctions campaign against Pyongyang.

There were "hundreds of new sanctions ready to go," he said, but they won't be imposed "until the talks break down." Trump added that he looks forward to the day the sanctions can be lifted.

His words mark a turnaround from last year when he engaged in a war of words with Kim over the regime's testing of nuclear weapons and ballistic missiles. Fears of war escalated as Trump threatened to "totally destroy" the regime and the North responded with a threat to detonate a hydrogen bomb over the Pacific Ocean.

A mood for reconciliation set in this year after Kim Jong-un expressed an interest in sending a delegation to the PyeongChang Winter Olympics in South Korea in February.

At a historic summit in April, South Korean President Moon Jae-in and Kim agreed to pursue "complete denuclearization" and a formal end to the 1950-53 Korean War. The conflict ended in an armistice, not a peace treaty, leaving the North technically at war with both the South and the US.

Trump said the issue could be discussed at his meeting in Singapore.

"We talked about it. We talked about ending the war," he said.

"That's something that could come out of the meeting. I think, really, that's something that maybe could come out of the meeting."

North Korea's abysmal human rights record could also be addressed

"Could be, yes, could be," Trump said. "I think we probably will, and maybe in great detail. We did not talk about human rights (today)."

Kim Yong-chol, vice chairman of the central committee of North Korea's ruling Workers' Party, is the highest-ranking North Korean to visit the US since 2000.

That year Vice Marshal Jo Myong-rok visited the White House and met with then President Bill Clinton.

Kim is under US sanctions for his alleged role in North Korea's nuclear weapons program and other illicit activities, including the 2010 sinking of a South Korean warship that killed 46 sailors.