"We had an opportunity to discuss the issue of S-400 with [Russian President Vladimir] Putin, though this issue is already closed, and there is nothing something negative to talk about here. I think that the deliveries will begin in the first half of July", Erdogan told reporters on board a plane on his way back from Tajikistan as quoted by the broadcaster CNN Turk.
On Saturday, Putin and Erdogan held a brief conversation in Dushanbe before the start of the summit of the Conference on Interaction and Confidence-Building Measures in Asia (CICA).
In December 2017, Moscow and Ankara signed an agreement for the delivery of the state-of-the-art S-400 systems. The Turkish decision to purchase the Russian missile defence systems angered the former's closest NATO ally, the United States. Washington has repeatedly relayed its concerns to Turkey that the systems might be incompatible with NATO standards, but Turkey has rebuffed all concerns.
Earlier in June, acting US Defence Secretary Patrick Shanahan formally informed Turkey that it would not be allowed to receive the US F-35 fighter jets it had already purchased if it went ahead with the S-400 deal.
Turkish officials have said that the purchase of military equipment is a sovereign right and ruled out the possibility of abandoning plans to acquire the S-400 systems.