Even if North Korea is willing to cooperate, dismantling its secretive weapons of mass destruction programs, believed to encompass dozens of sites, will be tough.
Bolton added that it would be to the North's advantage to cooperate to see sanctions lifted quickly and aid from South Korea and Japan start to flow.
New satellite photos show that Kim Jong Un is continuing to develop his nuclear weapons program, and USA intelligence sources say they believe North Korea has increased its production of nuclear fuel at multiple sites.
He said the one-year program the U.S. is proposing would cover all of the North's chemical and biological weapons, nuclear programs and ballistic missiles.
US Secretary of State Mike Pompeo reportedly plans to travel to North Korea this week to discuss denuclearization plans in a follow-up to the Singapore summit between US President Donald Trump and North Korean leader Kim Jong-un.
The report directly contradicts President Donald Trump's claim that "there is no longer a nuclear threat from North Korea".
We know exactly what the risks are of them using negotiations to drag out the length of time they have to continue their nuclear, chemical, biological weapons programs and ballistic missiles. -North Korean diplomacy prior to the Singapore summit.
At the same time, United States envoy Sung Kim held talks with North Korean officials on Sunday in the border village of Panmunjom within the demilitarised zone between the North and South Korea, South Korean media reported on Sunday.
Speaking to Fox, Trump also sought to shrink the perceived cost of the declared agreement falling through, seeking to frame his negotiations with North Korea as having been achieved without concessions.
Another U.S. official cautioned: "Work is ongoing to deceive us on the number of facilities, the number of weapons, the number of missiles. I really believes he means it".
Joel Wit, a former diplomat who helped the US negotiate with North Korea including a nuclear agreement between the USA and the regime in 1994, said the USA believed the rogue regime had two sites to "enrich nuclear fuel" including Yongbyon and another, but the name of the center was not revealed. Some aspects of the new intelligence were reported Friday by NBC News. Last summer, during his first one-on-one meeting with Putin, in Hamburg, Trump said that he questioned him about the interference accusations and that the Russian leader denied it.
Cronin, senior director of the Asia-Pacific Security Program at the Center for a New American Security, said he had heard from US and South Korea officials that Pompeo was expected to return to Pyongyang at the end of this week and that Sung Kim was working to prepare the way for that trip.
As of now, there is little proof that North Korea intends to go down that road, longtime North Korea observers say. Interviewed on NBC's Meet the Press, Lindsey Graham of SC said North Korea would "regret it" if nuclear talks collapsed.