"Later, we may work with S-500s," the next generation system, Erdoğan said.
U.S. officials have suggested that Turkey should buy U.S. Patriot missiles rather than the Russian system, arguing the S-400 is incompatible with NATO systems. But Turkish officials have said that Turkey will not go back on its agreement with Russia, even if it were to also buy Patriots.
Safe zone in Syria
"Because an attack from there [Syria] is possible at any moment.
"Let me tell you what they [the U.S.] will do; they will give control of this area to the YPG and PYD. It is not possible for Turkey to accept this."
"However, the U.S. must put an end to its ties with the PYD/YPG terror group."
In December, Trump announced plans to withdraw all 2,000 American troops from the war-torn country, saying the U.S.-led coalition had succeeded in militarily defeating ISIL.
Last month, however, the Trump administration backtracked, saying some 200-400 troops would remain in Syria as part of a peacekeeping effort.
U.S. military personnel have since said that a couple hundred troops will remain in the region, with forces staying in northeast Syria to create a "safe zone" as well as forces being stationed at the al-Tanf garrison in southern Syria.
US weapons in Syria
He stressed that Turkey faced the same problem in Iraq and the weapons had been left to the PKK terror group.
"If the U.S. is to take weapons out of Syria, they can, as they are their own property. However, if they won't, give them to Turkey. If it is needed, we can sit at the negotiating table and buy them. They must not give these weapons to the terrorists," he said, referring to the YPG/PKK.
World media monitoring