North Korea has conducted 10 missile tests since the beginning of 2017. (Kyodo News via Getty Images)

Yi said on Monday North Korea’s claim that the missile it tested could carry a new large-sized nuclear warhead is unfounded, adding the agency had not detected any unusual activity at North Korea's Punggye-ri nuclear test site.

Last Tuesday, North Korea said it successfully tested a new intercontinental ballistic missile, which they allege would be capable of striking anywhere in the world. North Korea already performed 10 missile tests so far this year.