North Korea tests upgraded solid-fuel engine for U.S.-range missiles

North Korea’s Kim Jong Un oversaw a ground test of an upgraded solid-fuel engine for missiles that could reach the U.S. mainland, part of a five-year effort to bolster the country’s strategic arsenal. Experts note solid-fuel tech offers mobility and concealability, though some skepticism remains about the test’s stated capabilities and timing, and there’s speculation about potential Russian cooperation; no location or duration details were disclosed.