The head of Russia's air force Col. Gen. Viktor Bondarev said Thursday that Russian fighter jets could be hijacked in countries neighboring Syria and used to attack Russian forces. Missile systems have therefore been sent to Syria to protect its military forces there. "We have calculated all possible threats,” he said. “We have sent not only fighter jets, bombers and helicopters, but also missile systems," Bondarev told Komsomolskaya Pravda newspaper. "We must be ready."