On Monday, the US Treasury slapped sanctions on four Turkish officials and the Presidency of Defence Industries, a federal office responsible for managing Turkey's defence industries. The restrictions are related to Ankara's purchase of the S-400, an advanced Russian-made air defence system.
"What kind of alliance is this? What is this based on?" Erdogan fumed in a televised address from Ankara on Wednesday, calling the restrictions an "open attack against" Turkey's "sovereignty," Erdoğan said.
"Refusing our conditions for the purchase of their [Patriot] air defence systems, the United States used the sanctions weapon because we purchased them elsewhere," he added.
Warning that sanctions were 'incompatible' with the US-Turkish status as allies, Erdogan announced that Turkey's defence sector would "work two times harder" amid the restrictions, and stressed that Washington 'will not stop' Turkey's efforts.
Erdogan was incorrect in suggesting that CAATSA had never been deployed against any nation except Turkey. In 2018, the US government used the law to target a Chinese defence procurement office and its director for "engaging in significant transactions" with Russia over its transfer of Su-35 fighter jets and S-400-related equipment to the People's Republic. US officials have also threatened to use CAATSA against the Nord Stream 2 pipeline project, and against India amid that country's plans to buy S-400s. Washington has not followed through on the latter two threats.