NEW YORK — One of North Korea’s most powerful figures will meet President Donald Trump on Friday at the White House as high-level talks in New York wrapped up with growing signs that the stalled nuclear disarmament summit between Trump and North Korean leader Kim Jong Un could take place in less than two weeks.

Kim Yong Chol, a North Korean spy chief and four-star general who is under U.S. sanctions, will deliver a letter to Trump from Kim Jong Un, the president told reporters in the latest whirlwind of high-stakes diplomacy aimed at reviving the proposed summit.

“I look forward to seeing what’s in the letter,” Trump said. Asked if an arms control deal was coming together, he said: “I think it will be very positive. … The meetings have been very positive.”

Trump said he hopes to sit down with Kim Jong Un in Singapore on June 12, as originally scheduled, but suggested follow-up meetings may be necessary to hammer out a disarmament deal.

“I want it to be meaningful,” Trump said of a possible summit. “It doesn’t mean it gets all done at one meeting. Maybe you have to have a second or a third. And maybe we’ll have none.”

The cliffhanger approach further highlights how Trump has tossed out the conventional playbook for his nuclear summitry. Aides say Trump believes his personal commitment and negotiating skills can help break the cycle of failure that have marked U.S. attempts to curb North Korea’s nuclear program since the 1990s.

Adding to the suspense, Secretary of State Mike Pompeo met with Kim Yong Chol for about 4½ hours in a U.S. diplomat’s home in a New York skyscraper, and later said the logistics, security and an agenda for a summit could be finalized in days.

“We’ve made real progress in the last 72 hours toward setting the conditions,” Pompeo told reporters. The flurry of logistical meetings have taken place in New York, Singapore and in the Demilitarized Zone that separates the two Koreas, each with different agendas.

“Our two countries face a pivotal moment in our relationship in which it could be nothing short of tragic to let this opportunity go to waste,” Pompeo added.

Pompeo outlined what he called “a brighter path for North Korea” if it agrees to nuclear disarmament. “We envision a strong, connected, and secure, prosperous North Korea that maintains its cultural heritage but is integrated into the community of nations.”

He conceded the sides still have not determined what steps they must take to satisfy the U.S. demand for what it calls “complete, verifiable and irreversible denuclearization” of the Korean Peninsula, and North Korea’s demand for ironclad security guarantees and easing of sanctions.

Pompeo and Kim Yong Chol held formal talks Thursday morning at the residence of the U.S. deputy representative to the United Nations, an apartment with a spectacular view of the East River. A second round of talks in the afternoon was scrubbed, though Pompeo denied a problem. “We didn’t end the talks early,” he said.

Pompeo acknowledged the obstacles of trying to wring a major disarmament deal with one of the world’s most reclusive states.

“There will be tough moments, there will be difficult times,” he said. “We’re decades into this challenge, and so one ought not to be either surprised or frightened or deterred … by challenges and difficulties, things that can’t be bridged. Our mission is to bridge them so that we can achieve this historic outcome.”

Still, Pompeo would not say the June 12 summit is definitively back on, nor when the world will know for sure.

Prospects for the Singapore summit have careened up and down as both sides threatened one another and engaged in diplomatic brinkmanship. After several days of escalating rhetoric, Trump announced May 24 that he was pulling out — and then jumped back in less than a day later.

With his travels to New York and Washington, Kim Yong Chol is the highest-ranking North Korean to visit the United States since 2000. Vice Marshal Jo Myong-rok went to the White House then in another period of hope and invited President Bill Clinton to Pyongyang to seal an accord to curb its ballistic missiles. Neither the visit, nor the deal, occurred.

Kim Yong Chol marks an unusual visitor to the White House, however. In 2010, the Obama administration placed him on a blacklist as chief of North Korea’s premier intelligence agency, the Reconnaissance General Bureau, and its role in the illegal export of arms and military equipment.

In 2015, the Obama administration blamed Gen. Kim for the cyberattack on Sony Pictures. South Korea has sanctioned him as well, accusing Gen. Kim of orchestrating several attacks on South Korean targets, including the torpedoing of a warship in 2010 that killed 46 sailors. The European Union also has sanctioned him.

Because of the sanctions, he needed a waiver from the State Department to visit New York, and another to travel to Washington to deliver the letter to Trump.

Special correspondent Sabra Ayres in Moscow contributed.

barbara.demick@latimes.com