Recep Tayyip Erdogan
Recep Tayyip ErdoganReuters

Turkish President Recep Tayyip Erdogan said on Sunday that the first delivery of the Russian S-400 missile defense system would take place within 10 days, Reuters reported.

Turkey and the United States, NATO allies, have been at odds over Ankara's decision to purchase the S-400s.

Washington says the S-400 poses a threat to the Lockheed Martin Corp F-35 stealthy fighters, which Turkey also plans to buy.

The US also believes the S-400 sale is part of Russian efforts to disrupt the alliance amid Western concern over Erdogan's burgeoning relationship with Putin.

Turkish officials insist that the deal to purchase the S-400 does not affect the security of the US and have repeatedly stressed that they will go ahead with the deal despite Washington’s objections.

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

The White House said Trump "expressed concern" over the S-400 deal and "encouraged Turkey to work with the United States on defense cooperation in a way that strengthens the NATO alliance."

Speaking to reporters after the G20 summit in Japan, where he held bilateral talks with Trump, Erdogan said he believed the dispute over the S-400s would be overcome "without a problem" and added that his US counterpart supported Turkey in the dispute.

"In our phone calls, when we come together bilaterally, Trump has not said so far: 'We will impose these sanctions.' On the S-400s, he said to me: 'You are right.' We carried this issue to a very advanced level," Erdogan said, according to Reuters.

Erdogan’s comments come a week after he said he would use his "good" relationship with Trump to try to defuse the crisis over the S-400 purchase.

On Sunday, Erdogan said the two leaders had agreed to delegate officials to follow the issue. He also said Turkish and US foreign and defense ministers would "open the doors" to resolving the matter.

US officials said recently that the United States has decided to stop accepting any additional Turkish pilots who planned to come to the United States to train on F-35 fighter jets due to the S-400 purchase.