American-made F-35 fighter jets cannot operate in the same airspace as the Russian S-400 missile system, said the US's top diplomat Wednesday, Anadolu reports.
"It is not possible to both fly the F-35 in space where the S-400 is significantly operable," Secretary of State Mike Pompeo told a Senate Foreign Relations Committee at a hearing.
He said the US relayed "this technical challenge" to Turkey through both diplomatic and military channels.
Following protracted efforts to purchase air defense systems from the US with no success, Ankara decided in 2017 to purchase Russia's system.
Washington warned Ankara of its purchase of the S-400 system, and last week suspended delivery of parts and other services related to the F-35 jets.
US officials suggested Turkey buy the US Patriot missile systems rather than the S-400 from Moscow, arguing it would be incompatible with NATO systems and expose the F-35 to possible Russian subterfuge.
Pompeo hinted at the possibility of sanctions through a law passed to punish a trio of other nations, because of the deal.
"The S-400 is a significant weapons system, and we've shared with them, we've asked them to go take a look CAATSA, what that might well mean for them," he said.
The Countering American Adversaries Through Sanctions Act, or CAATSA, was passed in 2017 to impose sanctions on Iran, North Korea and Russia and combat those countries' influences across the globe.
Pompeo said a deal for the American air defense system is now on the table, and that the US acknowledges Turkey's role in the F-35 program.
"We've made clear to the Turks as plainly as we can, they build a significant component of the F-35. Not only are they purchasers and customers, but they are part of the supply chain for the F-35," Pompeo said.
Turkey first joined the F-35 Joint Strike Fighter Program in 2002 and has invested more than $1.25 billion. It also manufactures various aircraft parts for all F-35 variants and customers.
Turkish firms have supplied the F-35 program with key components, including airframe structures and assemblies and the center fuselages.