MOSCOW( Reuters)-Russia scrambled two Sukhoi Su-30 fighter jets to escort a pair of U.S.B-1B strategic bombers over the Black Sea, Russia's defence ministry said on Wednesday, an incident that coincided with a visit to the region by the U.S. secretary of defense.... The supersonic U.S. Cold war-era planes were originally designed to carry nuclear bombs and missiles but now carry conventional payloads." Russian fighter crews identified the aerial targets as two U.S. Air Force supersonic strategi