(Bloomberg) -- North Korean leader Kim Jong Un wrote to President Donald Trump to set up a second meeting between the two leaders, but the correspondence won’t be publicly released unless the dictator gives his permission, White House Press Secretary Sarah Huckabee Sanders said.

Trump received the document on Monday, Sanders said, describing it as “a very warm, very positive letter.” The U.S. is “already in the process of coordinating” a second meeting between the leaders.

“We won’t release the full letter unless the North Korean leader agrees that we should,” she said at a briefing.

The letter is the latest direct communication between the two leaders, who held a summit in Singapore in June and agreed that North Korea would abandon its nuclear weapons program. But Kim’s regime has shown little sign it’s moving toward denuclearization, and Trump canceled a planned trip to Pyongyang by Secretary of State Mike Pompeo last month citing a lack of progress.

Sanders declined to say whether the leaders’ second meeting would be in Washington. “We’ll let you know when we have further details,” she said.

Kim told visiting South Korean envoys last week that he wants “goodwill measures” North Korea has taken to be reciprocated and expressed frustration with skepticism about his commitment to end the country’s nuclear program. Kim pressed for a formal peace agreement to end the 1950-53 Korean War, according to South Korean officials who briefed the media after the trip.

Kim has been eager to secure the formal declaration. But U.S. and South Korean officials have been wary of signing a document that could legitimize Kim’s control over half the peninsula without more concrete concessions, particularly a timeline for denuclearization and an agreement defining the term.

Pompeo told a Senate Committee in July that North Korea continues to produce fissile material that could be used in nuclear weapons. U.S. satellite photos and other evidence show North Korea continued to build intercontinental ballistic missiles in the weeks after Kim and Trump agreed to work toward denuclearization, according to a Washington Post report.

--With assistance from Youkyung Lee, Jihye Lee and Shannon Pettypiece.

To contact the reporter on this story: Justin Sink in Washington at jsink1@bloomberg.net

To contact the editors responsible for this story: Alex Wayne at awayne3@bloomberg.net, Mike Dorning, Joshua Gallu

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