After Turkey acquired the Russian S-400 missile system, the United States decided to end the F-35 deal before July 31, 2019. Acting Defense Secretary Patrick M. Shanahan had warned Turkey that such a deal with Russia risks undermining its ties to NATO. The US threatened Turkey with CAATSA sanctions over Turkey's decision to buy the S-400 missile defense system from Russia. In February 2019, Russia had an advance supply contract with Saudi Arabia for the S-400, Qatar was in “advanced” talks with Russia for the S-400, and India agreed to pay more than $5 billion for five S-400 squadrons to be delivered in 2023.