Turkey expects the delivery of the S-400 surface-to-air defense missile system from Russia to begin in July, President Recep Tayyip Erdogan was quoted as saying in Turkish media on June 16.
"I believe [S-400s] will begin to arrive in the first half of July," Erdogan said according to the CNN Turk broadcaster.
Ankara's deal with Moscow has been a major source of tension between Turkey and the United States.
Washington says the S-400 missiles are a threat to its F-35 fighter jet program and has told Turkey it would be banned from buying F-35s over the deal.
The United States has also warned Turkey of possible sanctions if it takes delivery of the Russian missile system.
U.S. acting Secretary of Defense Patrick Shanahan this month outlined how Turkey would be pulled out of the F-35 fighter jet program unless Ankara changed course from its plans to buy the missile systems.
Erdogan said he would discuss the issue with U.S. President Donald Trump when they meet at this month's Group of 20 summit.
Turkish Foreign Minister Mevlut Cavusoglu has said that Ankara will retaliate against any possible sanctions imposed by Washington over the deal.
