Turkish daily Yeni Safak said in a report on Saturday that the Turkish defense procurement authorities had called on the country’s military to formally consider the purchase of Su-35 jets from Russia.
Ankara, the paper said, would start official negotiations with the Russian state arms company Rosoboronexport if the military approved the proposal.
The administration of US President Donald Trump had threatened to expel Turkey from the F-35 fighter program if it acquired the S-400 from Russia.
Turkey began receiving deliveries of the surface-to-air S-400 systems on June 12 and the deliveries are set to continue through April 2020.
Last month, the US announced in response that it was beginning the process of removing Turkey, part of the manufacturing supply chain for the advanced aircraft, from the F-35 program. The US also halted any new training for Turkish pilots on the advanced aircraft.
Ankara later said Turkey would meet its defense needs elsewhere if Washington did not provide the country with the fifth-generation and multi-role combat aircraft.
Washington has expressed concerns that deploying the S-400 with the F-35 would allow Russia to gain too much inside information of the stealth system.
Ankara is striving to boost its air defense, particularly after Washington decided in 2015 to withdraw its Patriot surface-to-air missile system from Turkish border with Syria, a move that weakened Turkey’s air defense.
Additionally, Ankara’s ties with its Western allies in NATO have been strained over a range of issues.
Turkish President Recep Tayyip Erdogan has been critical of Washington for supporting Kurdish groups in Syria that he says are responsible for terror attacks inside Turkey.
The Turkish leadership has also slammed American officials for rejecting his requests to hand over Fethullah Gulen, a powerful opposition figure living in the US, whom Ankara accuses of having masterminded the July 2016 coup attempt, among other issues.