Erdogan and Trump held talks at the White House to overcome mounting differences between the allies. Washington has said the S-400s pose a threat to its F-35 stealth fighter jets and has suspended Turkey from the jet programme, where it is a buyer and manufacturer. It has also warned of US sanctions over the deal, but has yet to impose them.
Speaking to members of his AK Party in parliament, Erdogan also said he had told Trump that if the United States maintained its "uncompromising stance" on the F-35s, Turkey would have to seek alternatives to meet its medium-term defense needs, Reuters reported.
Turkey is also aware that the US support for the Syrian Kurdish YPG militia will not end immediately, President Tayyip Erdogan said Tuesday, but added that Ankara's battle against the militia it considers a terrorist group will continue.
Speaking to members of his AK Party, Erdogan said Turkey will continue to battle the YPG until all threats towards Turkey are stopped and every militant is eliminated.
He added that no plan in the region can be realized without Turkey's consent and support.