Turkey is given a two-week deadline to cancel its purchase of a Russian missile system, according the US media outlets.

If it receives its purchase of the S-400 next month, the country will be ousted from Lockheed Martin’s F-35 program and will not receive 100 of the fighter jets it has ordered, and will also face U.S.-imposed sanctions, CNBC reports.

Instead, the U.S. has proposed that Turkey purchase Raytheon’s U.S.-made Patriot missile defense system so it can remain in the F-35 program.

“NATO countries need to procure military equipment that is interoperable with NATO systems. A Russian system would not meet that standard. We underscore that Turkey will face very real and negative consequences if it completes its S-400 delivery,” a State Department official told CNBC.