Open this photo in gallery: North Korean leader Kim Jong-un visits an aircraft manufacturing plant in the city of Komsomolsk-on-Amur in the Khabarovsk region, Russia, on Sept. 15.MIKHAIL DEGTYAREV TELEGRAM CHANN/Reuters North Korean leader Kim Jong-un on Friday inspected a Russian fighter jet factory that is under Western sanctions, part of a visit Washington and its allies fear could strengthen Russia’s military in Ukraine and bolster Pyongyang’s missile program. Russian President Vladimir Putin and Kim discussed military matters, the war in Ukraine and deepening cooperation when they met at a summit on Wednesday. South Korea and the United States said...