SEOUL, Sept. 9 (UPI) -- North Korean leader Kim Jong Un oversaw the test of a solid-fuel engine for intercontinental ballistic missiles, calling it a "significant change" in Pyongyang's growing nuclear weapon capabilities, state media reported Tuesday. Kim oversaw the ninth and final test of the high-thrust engine on Monday, state-run Korean Central News Agency said. The development of the engine is a "success assuming the most strategic nature in the recent modernization of defense technology