"I am very confident in the Patriot proposal that we've delivered to Turkey, its availability, its pricing, and very importantly, the industrial participation that comes along with the Patirot system," Shanahan told reporters, according to a Pentagon pool report. "I expect we'll solve the problem so that they have the right defence equipment in terms of Patriots and F-35s."
This comes after on Monday a State Department official told Sputnik that Washington issued a warning to Ankara that it could face even more consequences including sanctions for purchasing Russian S-400 defence systems.
Earlier that day, the United States halted shipments to Turkey of equipment related to the fifth generation F-35 fighter aircraft over the country's plans to purchase Russian S-400 air defence systems, Reuters reported.
In December 2017, Russia and Turkey signed a loan agreement for the supply of S-400s.