ANKARA, Turkey — Russia is “ready to cooperate” with Turkey to sell its new-generation Su-57 fighter jet in case the Ankara government and Turkish companies are expelled from the U.S.-led F-35 program, according to a senior Russian defense official.

“These fifth-generation Russian fighter jets [Su-57] have outstanding qualities, and show promise for export,” said Sergei Chemezov, head of Russia’s state-owned Rostec Corporation, in an interview with Ankara-based international news agency Anadolu.

Chemezov’s statement came in confirmation of an Apr. 19 Defense News story that said if U.S. officials were to expel Turkey from the multinational group that builds the F-35, Turkish defense officials likely would pursue Russian fighter jet technology.

“We cannot afford to leave the F-35 not substituted,” a senior Turkish military officer told Defense news. He declined to comment on the replacement options, as this would require “technological, economical and political deliberations.”

But a defense procurement official said a “geostrategic assessment” would make Russian options emerge as the natural choice. “Russian fighter technology would the first best choice if our American allies behaved in an un-allied way and questioned Turkey’s membership in the Joint Strike Fighter program,” the official said.

Washington has threatened to expel Ankara from the multinational program if Turkey deploys the Russian-made S-400 surface-to-air missile system on its soil.

If Turkey accepts the S-400, “no F-35s will ever reach Turkish soil. And Turkish participation in the F-35 program, including manufacturing parts, repairing and servicing the fighters, will be terminated, taking Turkish companies out of the manufacturing and supply chain for the program,” wrote a group of bipartisan lawmakers from the Senate Armed Services Committee and Senate Foreign Relations Committee.