"I'm not saying Turkey will buy S-400s, it already has. We have sealed the deal," Erdogan said at a Justice and Development Party (AK Party) meeting.
The president reminded that the S-400 agreement with Moscow was appealing not only because of the price but also due to technology transfer and the possibility of joint production.
Addressing the U.S.' plans to wind down Ankara's involvement in the F-35 program over the purchase, Erdogan pointed out that Turkey was not only a client but also a production partner that invested over $1 billion in the project.
"We will meet with President (Donald) Trump in Japan at the end of the month, where we already have meetings planned. I hope there will be a mutual discussion of these issues," he said.
The Pentagon last week told Turkey that it was cutting off Ankara's purchase of F-35 fighter jets if the Turkish government went ahead with plans to buy a Russian missile defense system, ratcheting up what has been a lengthy, heated dispute between the two NATO allies.