"I said no matter what package of ... S-400s we get, we can buy from you a certain amount of Patriots," President Recep Tayyip Erdogan told the 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 Erdogan, Anadolu Agency reported.
Erdogan had earlier talked about buying Patriots with US President Donald Trump in a telephone call and the two will discuss the issue in more detail at the UN General Assembly meetings in New York later this month.
"In my opinion a country like the US will not want to hurt its ally Turkey any more. This is not a rational behavior," Erdogan said, who expressed hope that his personal bond with Trump would overcome the current crisis between two countries.
"This is not an offense, but a defense system. Turkey needs such a defense system,” he said.
Underlining that Trump blames the Obama administration for refusal to sign a deal with Turkey to sell the Patriot missile system, Erdogan said: “It is impossible to think that threats of sanctions reflect reality.”
He also reiterated that Turkey would take care of itself if Washington continued its current stance on Turkey's exclusion from the F-35 fighter jet program.
Highlighting that Russia supports Turkey in the defense industry, Erdogan stressed that Russia offered Turkey to sell fighter jets Su-57 and Su-35.
In July, the US 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 a partner in the jet program. It has warned any effort to remove it from the production chain would be very costly.