N.Korea 'Kept Making Nukes During Hanoi Summit'

North Korea continued to produce nuclear weapons even in February last year when North Korean leader Kim Jong-un met with U.S. President Donald Trump in Hanoi with a promise of "complete denuclearization," a U.S. State Department report suggests.

In the report submitted to Congress on Tuesday, the State Department said, "Throughout 2019, the United States continued to have significant concerns regarding North Korea's nuclear weapons program and its continued production of fissile material."

Washington "remains ready to engage North Korea in a constructive negotiation; however, until final, fully verified denuclearization is achieved, the international community remains united. UN and U.S. sanctions will remain in place and will be fully enforced," it added.

Quoting a report from the International Atomic Energy Agency, the State Department said North Korea kept operating nuclear facilities in 2018 and 2019 while U.S.-North Korea summits and working-level talks were underway.

"There were indications of ongoing mining, milling and concentration activities at locations previously declared as the Pyongsan uranium mine and Pyongsan uranium concentration plant," it added. There also were indications of a "centrifuge uranium enrichment facility at the Yongbyon Nuclear Fuel Rod Fabrication Plant, including the operation of the cooling units," it said.

The State Department said the movement of major reactor components was also observed at the experimental light-water reactor construction yard at Yongbyon. "It may be intended to provide North Korea with a civilian justification to possess uranium enrichment technology that could be used to produce fissile material for nuclear weapons," it speculated.

The report says that the results of dismantlement at Punggye-ri nuclear test site in May 2018 are "almost certainly reversible." "The United States believes there is a possibility of additional unidentified nuclear facilities in North Korea," it says. "It is also possible that North Korea could develop another nuclear test site, if it chose to do so."

It speculates that North Korea may also have amassed bioweapon materials that the military could use.

In a virtual seminar hosted Tuesday by the Asia Society, a U.S. non-profit organization, Marc Knapper, the deputy assistant secretary of state for Korea and Japan, said, "We're really unified in our view that the door to diplomacy remains open."

"We remain ready to engage in dialogue with the North, and we remain committed to a diplomatic solution to address the nuclear and missile issues."

Meanwhile, in a report titled "The Impact of Artificial Intelligence on Strategic Stability and Nuclear Risk," the Stockholm International Peace Research Institute expressed concerns over the possibility of North Korea using artificial intelligence to disturb the U.S.' nuclear command, control, and communications (NC3) system.

North Korea’s cyberwarfare agency Bureau 121 is greatly interested in cyber operations against the U.S.' NC3 system, according to SIPRI.

The North is planning so-called "Zero Day" cyberattacks which could strike South Korea and the U.S. before they find and remedy weaknesses of their systems. The nuclear deterrence the U.S. is providing to South Korea could be incapacitated if such attacks should be launched on the U.S.' NC3 system, the SIPRI warned.