These weapons will undertake combat missions at Russian military complexes in Syria.
Video from the Russian Defense Ministry shows four S-400 "fire dragons" being sent to Syria, two of which to the Hmeimim air base, the remaining two to the naval base in Tartus.
The S-400 is the latest generation of Russian air defense systems in use. It is designed to destroy aerodynamic targets and ballistic missiles.
According to manufacturer Almaz Antey, an S-400 unit can attack 36 targets at the same time.
In 2015, Russia deployed the S-400 to the Hmeimim air base to ensure the safety of fighter jets operating against IS in Syria. The deployment comes after a Russian Su-24 bomber was shot down by Turkey.
