The U.S. will cancel the sale of F-35 fighter jets to Turkey after Ankara decided to buy a rival missile defense system from Russia, U.S. President Donald Trump confirmed Tuesday.

Russia’s S-400 is considered one of the most advanced air-defense systems in the world.

The U.S. has long argued Turkey’s purchase of the Russian system not only risks the security of NATO members, it also violates the 2017 law threatening sanctions for any purchase of sophisticated Russian technology — the Countering Russian Influence in Europe and Eurasia Act of 2017.

Trump blamed the Obama administration for never reaching a deal to sell a comparable American missile defense system to Turkey.

“Because they have a system of missiles that’s made in Russia, they’re now prohibited from buying over 100 planes,” Trump said of Turkey during in a Cabinet meeting. “I would say that (F-35 manufacturer) Lockheed isn’t exactly happy. That’s a lot of jobs. And frankly I’ve always had a very good relationship” with Turkish President Recep Tayyip Erdoğan, Trump said.