North Korea tests upgraded solid-fuel engine, signaling ICBM ambitions

North Korea conducted a ground test of an upgraded solid-fuel engine for missiles that Pyongyang says could target the U.S. mainland, with Kim Jong Un overseeing the test. KCNA said the engine’s thrust reached 2,500 kilonewtons, up from about 1,970 kN in a prior test. Analysts say the claim may be exaggerated and some data was not disclosed, and no launch has proven an operational ICBM, but the test highlights a drive to field faster, more mobile nuclear-capable missiles as part of a five-year arms buildup.