Turkish President Recep Tayyip Erdogan said Tuesday that there was now no way Ankara would backtrack from its deal with Russia on purchasing the S-400.
"There is a certain step that we took, there is an agreement here [with Russia] and we are committed to it. It is out of the question for us to take a step back", Erdogan said, according to Reuters.
Erdogan added that the recent US offer to sell Turkey its Patriot PAC-3 air defence platform simply wasn't as good as the Russian offer. "Unfortunately, the US side has not given us an offer as good as the S-400s", he said, noting that discussions with the US were ongoing.
Also Tuesday, Kremlin spokesman Dmitry Peskov said that Turkey was free to discuss the S-400 deal "with any third state" and was "not obliged to notify [Russia]" about such talks.
Last week, Acting US Defence Secretary Patrick Shanahan said he was unaware of any plans to create a joint working group on the S-400s. "The S-400 is designed to shoot down the F-35. They are natural enemies, that's the fundamental reason [Turkey shouldn't buy them]", Shanahan said.
On Thursday, Acting Assistant Secretary of Defence for International Security Affairs Kathryn Wheelbarger warned the delivery of S-400s to Turkey would be "devastating", adding that it would be "inconceivable to imagine Russia not taking advantage" of opportunities to collect information on US and NATO systems including the F-35.
Washington has reportedly given Ankara until the end of the week to abandon the S-400 deal or face penalties that may include everything from sanctions to blocking delivery of Turkey's F-35 jets.about $2.5 billion. Washington proposed selling a party of Patriot air defence systems to Turkey in place of the S-400s for $3.5 billion, but Turkey refused, indicating that it might still buy Patriots, but not in place of its S-400s.
Once deliveries start in July, Turkey will be just the fourth country in the world to possess the S-400, which is designed to stop enemy aircraft, drones, cruise, and ballistic missiles. The system is currently the most advanced mobile air defence platform in Russia's arsenal.