"At the moment, the opinion of the [US] administration is developing in a positive direction. Of course, the US is not the only way out for us. If necessary, as with the S-400 systems, we are negotiating alternatives outside of the United States … We have alternatives," Erdogan told reporters.
The situation regaring Ankara's purchase of US-made fighters was complicated in July as the US House of Representatives passed an amendment to the National Defense Authorization Act constraining the transfer of F-16 fighter jets to Turkey. The legislation required assurances on behalf of the US president that the aircraft will not be used for unauthorized territorial overflights in Greece.
While both countries are NATO members, Ankara and Athens are engaged in a standoff over their interests in the Aegean Sea and the Eastern Mediterranean.
Previously, reports also suggested that if the deal falls through, Turkey may resort to buying Eurofighter Typhoon combat aircraft or Russia's Su-35 instead.