Turkey’s Foreign Minister Mevlut Cavusoglu considers the purchase of Russian S-400 surface-to-air missile systems to be a done deal that cannot be canceled, TASS reports, citing Reuters.

"The current deal [purchase of Russian S-400 Triumf missile systems] is a done deal, I cannot cancel it," Reuters quoted Cavusoglu as saying after a meeting with his US counterpart Mike Pompeo.

The minister added that Ankara needs further defense procurement from its allies. "But I need more … and I prefer to buy from my allies," he said.

On November 14, the Anadolu news agency reported with reference to a high-ranked source in Washington that the US suggests that the Russian S-400 missile systems purchased by Turkey pose a threat to the F-35 fighter jets, which is why the United States could impose sanctions against Ankara. According to the source, Russian systems are problematic from the viewpoint of integration into the NATO systems.