SEOUL — North Korea can miniaturize a nuclear warhead small enough to be equipped on its short-to-medium-range ballistic missiles faster than other nuclear powers, a researcher argued at a conference in Seoul on Friday.

The comments were made in a session titled, “North Korean nuclear and missile technology developments: present situation and prospects,” which was part of a larger conference assessing inter-Korean relations, North Korea’s economy and domestic policies.

“Countries which have above-the-middle class science technology like North Korea can significantly shorten the time required from the first nuclear test to developing a nuclear warhead since they can exploit the