Turkish President Tayyip Erdogan said the first delivery of the Russian S-400 missile defense system would take place within 10 days, Turkish media reported on Sunday, a day after he said there would be no US sanctions over the deal.

Turkey and the United States, NATO allies, have been at odds over Ankara's decision to purchase the S-400s, with Washington warning of US sanctions if the delivery took place. Turkey has dismissed the warnings, saying it would not back down.

"Within 10 days, maybe within one week, the first shipment will have arrived. I told Trump this openly," Erdogan was cited as saying by Hurriyet newspaper after a meeting with US President Donald Trump.

The United States says the S-400s will compromise its Lockheed Martin Corp F-35 fighter jets, of which Turkey is a producer and buyer. 

Washington has also formally started the process of expelling Turkey from the F-35 program, halting the training of Turkish pilots in the United States.

But on Saturday, Erdogan said Trump had told him there would be no sanctions over the Russian deal, after Trump said Turkey had been treated unfairly over the move.

After Erdogan's comments, the Turkish lira strengthened 1.5 percent early on Monday to below 5.7 against the dollar. The dispute over the S-400s has long been a source of concern for investors.