Ankara will discuss purchasing U.S. Patriot missiles in a meeting between the two countries' leaders later this month, Turkey's president said on Friday.
"I said no matter what package of ... S-400s we get, we can buy from you a certain amount of Patriots," President Recep Tayyip Erdoğan told Reuters news agency in an interview in Istanbul.
"But I said we have to see conditions that at least match up to the S-400s," added Erdoğan.
Erdoğan had earlier talked about buying Patriots with Donald Trump in a phone call and they will discuss the issue in more detail with Trump at the UN General Assembly in New York later this month.
"In my opinion a country like the U.S. will not want to hurt its ally Turkey any more. This is not a rational behavior," Erdoğan said.
Erdoğan also expressed hope that his personal bond with Trump would overcome the current crisis between two countries.
In July, the U.S. suspended Turkey's involvement in a program for F-35 fighter jets, saying its purchase of the Russian S-400 missile defense program could endanger the aircraft, a claim Turkey has consistently denied.
Turkey produces some parts of the F-35 jets and is also a partner in the jet program, and has warned any effort to remove it from the production chain would be very costly.