Kathryn Wheelbarger , assistant secretary of defense for international security affairs, said Turkey's plan to buy the S-400 would hurt Turkey's ability to work with the Western coalition and force Washington to impose sanctions on Ankara, AFP reported.
"Completion of this deal will be catastrophic, not only for the F-35 program, in which the West has developed its modern integrated air capabilities, but it is also likely to disrupt the co-operation between Turkey," said Kathryn Wheelbarger at a seminar at the Atlantic Council in Washington.
She pointed out that the United States believes that Turkey is seeking the deal for Russia's support in the face of the Kurds along the border with Syria.
But Ankara warned that Russia is not a "reliable" long-term partner, does not support its military sales by maintenance, and is simply trying to "undermine" NATO's cohesion.
Trump's administration, even if it does not want to punish Turkey, may be forced to do so by pressure from Congress.