WASHINGTON — The North Korea nuclear summit is back on.

President Donald Trump announced the decision after a historic and lengthy Oval Office meeting Friday with Kim Yong Chol, who is the top deputy to North Korean leader Kim Jong Un.

"We'll be meeting on June 12 in Singapore," Trump told reporters at the White House. But he also said that it would be hard to reach a deal from a single meeting in less than two weeks.

"I don't see that happening," he said. "It will be a beginning. I’ve never said it happens in one meeting."

Trump's original plan to sit down with Kim Jong Un in Singapore June 12 was temporarily derailed after Kim Jong Un interpreted top U.S. officials' public discussion about following the "Libya model" in North Korea as a threat. Trump wrote a letter canceling the summit May 24, but held out hope it could be rescheduled.

On Friday, Trump made a concession to Kim Yong Chol.

"We had hundreds of new sanctions ready to go on and ... I said that I’m not going to put them on until such time that the talks break down," Trump said. "Why would I do that when we’re talking so nicely?"

At a minimum, Trump is eager to convince Kim Jong Un to curtail his capacity to reach the United States with nuclear weapons, and the North Koreans want relief from crippling U.S. and international sanctions. A State Department official said Thursday that the U.S. is still looking for an agreement from Kim to give up all of his nuclear capabilities.

For Trump, who has mused about winning a Nobel Peace Prize if he's able to cut a deal with Kim Jong Un, the summit is an opportunity to show that he can work toward nonproliferation in the shadow of his decision to walk away from the Iran nuclear agreement negotiated by President Barack Obama's administration.

For Kim, it's a chance to start bringing his isolated nation back into what Western diplomats like to call the community of nations. As Trump has pointed out, that could be a huge economic boon for North Korea.

"I think they want to do that. I know they want to do that," Trump said of North Korea giving up weapons. "They want other things along the line. They want to develop as a country ... We’re going to help in the process."

North Korea would also like to see a formal end to the Korean War and the removal of U.S. troops from the peninsula it shares with South Korea.

Trump said that the discussion with Kim Yong Chol, which lasted well more than an hour and included White House Chief of Staff John Kelly and Secretary of State Mike Pompeo, delved into sanctions specifically.

"We would not take the sanctions off unless they did" denuclearize, he said. "I look forward to the day when I can take the sanctions off of North Korea."

Kim Jong Chol presented Trump with a letter from his boss, which Trump described as "very nice" before acknowledging that he hadn't yet read it.

But the president said he was pleased with the status of the talks, calling the Oval Office confab a "getting-to-know-you-plus meeting."

South Korea's president’s office said in a statement Friday night ET that Trump's acceptance of Kim Jong Un's letter shows the road toward a summit between the U.S. president and the North Korean leader has become "solidified."

"We will watch the historic meeting in Singapore calmly yet with thrill," said Kim Eui-kyeom, South Korea’s presidential spokesperson.