According to the Turkish defence ministry, the first parts of the S-400 air defence system were flown to a military air base near Ankara, sealing a deal with Russian Federation that Washington had laboured for months to prevent.
But Turkish President Recep Tayyip Erdogan said after meeting U.S. counterpart Donald Trump last month that he was confident Ankara would not face sanctions for buying the Russian missile system.
The first S-400 parts delivered at Murted air base, the defence ministry tweeted.
The S-400 consignment was delivered to the Murted Air Base outside the capital Ankara, the ministry said in a statement which triggered a weakening in the Turkish lira to 5.712 against the dollar from 5.683 before the announcement.
Turkish President Recep Tayyip Erdogan seems to believe that, whatever the Pentagon may say, Donald Trump himself is less hostile to the purchase of the Russian missiles.
"The delivery of parts belonging to the system will continue in the coming days", Turkey's defence industry directorate said separately.
US officials have fretted that Turkey's possession of the S-400 could give Russian Federation access to secrets of the F-35's stealth technology.
The US says the Russian military hardware is not compatible with North Atlantic Treaty Organisation systems and that the acquisition may lead to Ankara's expulsion from an F-35 fighter jet programme.
Sanctions would mark a new low in the already-tense relations between Turkey and the U.S. Last year, the United States imposed sanctions on Turkey over its detention of an American pastor, triggering a Turkish currency crisis.
Investors in Turkey have been concerned about the impact of potential USA sanctions on an economy which fell into recession after a currency crisis past year.
Turkey has refused to bow to USA pressure, insisting that choosing which equipment to purchase is a matter of national sovereignty.
The F-35A is one of the world's most advanced military aircraft.
"We've always said regarding the S-400s that it's an agreement that has been finalised and the process continues to progress", Turkish Foreign Minister Mevlut Cavusoglu told reporters.
The Murted base, northwest of Ankara, was formerly known as Akinci Air Base. But Turkey says the offer does not meet its requirements, including possible future joint production.
Turkey could face expulsion from the F-35 program under the sanctions.
The US has already stopped training Turkish pilots on the F-35, and given Ankara until the end of July to get its personnel out of the US.
The S-400 missile system can engage targets independently as well as after receiving data from other radars.