White House national security adviser John Bolton said on Sunday he believed the bulk of North Koreas weapons programs could be dismantled within a year as questions have been raised about President Donald Trumps insistence that Pyongyang was "no longer a nuclear threat." Bolton told CBSs "Face the Nation" that Washington has devised a program to dismantle North Koreas weapons of mass destruction - chemical, biological and nuclear - and ballistic missile programs in a year, if there is full cooperation and disclosure from Pyongyang. "If they have the strategic decision already made to do that and theyre cooperative, we can move very quickly," he said. "Physically we would be able to dismantle the overwhelming bulk of their programs within a year." He said Secretary of State Mike Pompeo will likely discuss that proposal with the North Koreans soon. The Financial Times reported that Pompeo was due to visit North Korea this week but the State Department has not confirmed any travel plans. But reports that North Korea intends to secretly maintain some of its nuclear stockpile and production facilities raised questions Sunday. The Washington Post cited four unnamed US officials who, it said, had seen or been briefed on new intelligence findings that point to preparations for deceiving the United States. The Posts report came after NBC News said the North has been increasing nuclear weapons fuel production. The reports followed Trumps boast that the summit denuclearization pledge made by North Korean leader Kim Jong Un in Singapore had effectively ended the Norths nuclear threat, after months of inflammatory language from both sides.  The Post said the evidence of North Korean cheating had emerged since the June 12 summit, where Kim and Trump signed a pledge "to work towards complete denuclearization of the Korean Peninsula."  The stock phrase failed to clearly define denuclearization or produce a specific timeline towards dismantling the Norths atomic weapons arsenal. It also stopped short of longstanding US demands for North Korea to give up its atomic arsenal in a "verifiable" and "irreversible" way. On Sunday Trump stuck by his confidence in the Norths efforts. "I think theyre very serious about it," Trump said during during an interview on Fox News "Sunday Morning Futures."  Asked how he could trust Kims vow to denuclearize, Trump replied: "We had great chemistry. I made a deal with him. I shook hands with him. I really believe he means it."