North Korean leader Kim Jong-un has called for increasing the number of centrifuges for uranium enrichment in order to increase the nuclear weapons for self-defense, the state media said Friday.Kim made the call during a visit to the Nuclear Weapons Institute and the production base of "weapon-grade nuclear materials," according to the Korean Central News Agency (KCNA). The dispatch did not release the location of the facilities or date of the inspection.It marks the first time that the North has publicly disclosed an uranium enrichment facility.During the visit, Kim "stressed the need to further augment the number ofcentrifuges in order to exponentially increase the nuclear weapons for self-defence true to the Party's line of building up the nuclear armed force," it said.Source: Yonhap News Agency