North Korea conducts test for missile it claims can target U.S. mainland

North Korea on Sunday conducted a missile test for an upgraded solid-fuel engine it says can reach the U.S. mainland, according to state media. The country reported the engine’s maximum thrust is 2,500 kilonewtons, noting an increase from a 1,970 kilonewtons test in September, according to the official Korean Central News Agency.  The test took…