According to spy agencies, the Asian nation is presently building at least one liquid-fueled intercontinental ballistic missile (ICBM) at a research facility in Sanumdong, on the outskirts of Pyongyang, the national capital.

The latest finds contradicts US President Donald Trump's claim that North Korea no longer possess a nuclear threat.

Reports about North Korea's secret uranium-enrichment facility have also made the headlines.

Earlier this month, US agencies stated that North Korea had honoured a promise made last month during the June 12 meeting between Trump and Kim Jong-un, by dismantling a satellite launching station.

However, experts have said that the said facility can be rebuild in 10 months.

Jeffrey Lewis, director of the East Asia Nonproliferation Program at the James Martin Center for Nonproliferation Studies, said that Kim's administration is not willing to give up their nuclear weapons, instead, are looking for the recognition of their stock.

"We have this backward. North Korea is not negotiating to give up their nuclear weapons,” Lewis was quoted as saying by the US daily.

“They are negotiating for recognition of their nuclear weapons. They’re willing to put up with certain limits, like no nuclear testing and no ICBM testing. What they’re offering is: They keep the bomb, but they stop talking about it.”