Russia and Turkey will open negotiations about the possible purchase by Ankara of the advanced Russian-made S-400 air-defense system.
RFE/RL: Turkey mulls buying advance Russian air-defense system
A picture shows two Russian S-400 Triumf S-400 Triumf missile system at the Russian Hmeimim military base in Latakia province, in the northwest of Syria, on December 16, 2015. (AFP)
