MOSCOW: Assistant Secretary of State for European and Eurasian Affairs Wess Mitchell on Tuesday said, the United States threatened to impose sanctions on Turkey, if it buys Russia's S-400 air defense systems.
It would be hard to restore relations between the US and Turkey if this happens, he added.
"We made it clear that is Turkey buys S-400s. there will be consequences. We will introduce sanctions within Countering America's Adversaries Through Sanctions Act (CAATSA)," Sputnik quoted Mitchell as saying.
He further revealed that the US can withhold the transfer of F-35 combat aircraft to Turkey over national security concerns if Ankara decided to purchase the S-400s.
"We believe that we have the existing legal authorities that would allow us to withhold transfer under certain circumstances, including national security concerns," Mitchell told the US Senate Foreign Relations Committee.
Prospects for Turkish military-industrial cooperation with the United States would also be in jeopardy, Mitchell warned, if the S-400 air defence systems are purchased.
Earlier this month, Turkish Foreign Minister Mevlut Cavusoglu slammed Washington for creating artificial crises is the West's style, referring to the Senate's move to block F-35 supplies over Ankara's intention to buy Russia's S-400 air defence systems.
Earlier, in April, Russian state arms exporter Rosoboronexport's director general said that Russia had started working on the manufacturing of S-400 systems for Turkey.
The Russia-Turkey deal has prompted disagreements between Ankara and Washington as it believes that the weapon is incompatible with NATO's defences.