The factories have innocuous names, but analysts say several ostensibly civilian facilities visited by North Korean leader Kim Jong Un recently are also used to build ballistic missile launchers and other weapons.
On Saturday, North Korea state news agency KCNA released reports of Kim providing "field guidance" at a number of factories and cities, without specifying when the visits occurred.
While the reports only mentioned economic elements, the sites help form the core of North Korea's arms industry, and have played a major role in developing its intercontinental ballistic missile (ICBM) technology, according to analysts at the James Martin Center for Nonproliferation Studies (CNS) in California.