US Secretary of State Mike Pompeo will embark on a trip to North Korea Thursday to discuss an American plan that would lead to the dismantling of the Pyongyang’s nuclear and missile programs in a year. This will be his third visit to the country in three months and the first since the landmark June 12 Singapore summit between President Donald Trump and Kim Jong Un, during which the North Korean leader agreed to “work toward denuclearization of the Korean Peninsula.” The joint summit statement, however, gave no details on how or when Pyongyang might give up its weapons. US officials have since been trying to flesh out details to produce an agreement that might live up to Trump’s enthusiastic portrayal of the outcome. Despite Kim’s pledge, doubts have been mounting about Pyongyang’s willingness to abandon its weapons program. The State Department said Pompeo would head on Saturday from Pyongyang to Tokyo, where he would discuss North Korean denuclearization with Japanese and South Korean leaders. In announcing Pompeo’s travel plans on Monday, White House spokeswoman Sarah Sanders said the United States was “continuing to make progress” in talks with North Korea. She declined to confirm or deny recent media reports of intelligence assessments saying North Korea has been expanding its weapons capabilities. North Korea has been showering the US and South Korea with goodwill gestures in recent months, including the shutdown of its main nuclear testing site and the release of three American detainees. But many experts say nothing it has done is consequential enough to be seen as a sign that the country is willing to fully surrender its nuclear weapons. An NBC News report on Friday quoted US officials saying US intelligence agencies believe North Korea has increased production of fuel for nuclear weapons at multiple secret sites in recent months and may try to hide these while seeking concessions in talks with Washington. The Washington Post reported on Saturday that US intelligence officials had concluded that North Korea did not intend to fully give up its nuclear arsenal and is considering ways to hide the number of weapons it has. A US official told The Associated Press that the Posts report was accurate and that the assessment reflected the consistent view across US government agencies. An analysis of recent satellite photos also indicated that North Korea is completing a major expansion of a factory in the northeast that produces key parts of nuclear-capable missiles, two researchers at the Middlebury Institute of International Studies at Monterey, California, said in a joint post Monday. "The expansion suggests that, despite hopes for denuclearization, Kim Jong Un is committed to increasing North Koreas stockpile of nuclear-armed missiles," Jeffrey Lewis and Dave Schmerler said. Nam Sung-wook, a professor at Korea University in South Korea, said the US officials or academics speaking out likely aimed to put pressure on both North Korea and Trump. "First, they would want to say that they have lots of intelligence on North Korea and that its relations with the US would go back to the past if it doesnt take practical disarmament steps," Nam said. "Secondly, they likely targeted (Trump), asking if he was deceived by North Korea because no progress has been reported in the three weeks after the summit." Analyst Hong Min at Seouls Korea Institute for National Unification downplayed the significance of the new disclosures, saying Pyongyang and Washington have not yet agreed on detailed disarmament steps the North is obliged to take. US National Security Adviser John Bolton refused to comment on intelligence matters, but said the US was going into nuclear negotiations aware of Pyongyang’s failure to live up to its past promises.