The reports emerged just days after the second Trump-Kim summit in Hanoi, which finished abruptly without any deal or declaration due to the parties' failure to agree on the scale of North Korea's denuclearization and US-led sanctions relief.
"The North Koreans, obviously, would like to give up as little of their nuclear, biological and chemical weapons and ballistic missile programs as they could, in exchange for a very broad sanctions relief", Bolton told Fox News on Thursday, stressing that Donald Trump "wasn't buying" such an approach during the negotiations at the Hanoi summit last week.
Kim had agreed to shutter Sohae at a summit with the South's President Moon Jae-in in Pyongyang as part of confidence-building measures, and satellite pictures in August suggested workers were dismantling the engine test stand.
Observers say follow-up talks could be in doubt with USA monitors saying North Korea's missile engine test site appears to have been rebuilt to normal operational status following the breakdown of the Hanoi Summit. Furthermore, Yonhap news agency ran a report claiming the North is operating uranium enrichment facilities at its Yongbyon site. "I don't think I will be" disappointed, Trump said, "but we'll see what happens".
The now-defunct Marine Chain, a Hong Kong-based company in the business of buying and selling ships around the world using blockchain technology is also suspected of supplying cryptocurrencies to the North Korean government.
It's not the first time Carter has offered to help the Trump administration manage the delicate issue.
In a specific case, 10 million users of South Korean e-commerce portal Interpark are said to have had their personal information stolen.
A panel of experts from the United Nations (UN) has reportedly recently revealed that North Korea has attacked cryptocurrency exchanges to bypass economic sanctions and obtain foreign currency.
The US State Department said it could not comment on intelligence matters.
Commercial satellite imagery, 38 North said, "indicates construction to rebuild the launch pad and engine test stand that began before the Hanoi summit has continued at a rapid pace".
A U.S. government source, who did not want to be identified, said North Korea's plan in rebuilding the site could have been to offer a demonstration of good faith by conspicuously stopping again if a summit pact was struck, while furnishing a sign of defiance or resolve if the meeting failed.
Despite his sanctions talk, there have been signs across Asia that the United States "maximum pressure" sanctions campaign against North Korea has sprung leaks.
North Korean media have given conflicting signals on US relations, while appearing to target Bolton as a spoiler.
It also showed a stone-faced Bolton during a meeting in Hanoi, while Trump and other USA participants were all smiles.
"All parties should have reasonable expectations on this", Wang told a news briefing. South Korea and the United States have formally signed a deal that increases Seoul's financial contribution for the deployment of USA troops in the Asian country.
"We have sufficient time", he said, without mentioning a deadline for reaching an agreement so the goal could be met.