The crews of the latest S-400 Triumf air defense missile systems assumed combat duty in the Primorye Region in the Russian Far East, according to the press office of the Eastern Military District for the Pacific Fleet. “The S-400 Triumf surface-to-air missile complexes were deployed on the positions to protect the Primorye airspace,” TASS said, citing the statement on Friday. The air defense regiment earlier operated S-300 missile systems, which had proven their worth as reliable air defense systems, the military said.