Photo:Xinhua

In 2017, Turkey signed a deal with Russia to buy several S-400s, prompting the US to suspend shipments of fifth-generation F-35 fighter jets to Ankara. Washington says the Russian air defence system are "incompatible" with its F-35s.

The fact that other countries are demanding Turkey ditch the S-400 air-defence systems it purchased from Russia is unacceptable, Turkish Foreign Minister Mevlut Cavusolgu told reporters during a visit to Athens.

"We will have full control of the S-400 systems. Our technicians went to Russia to undergo training but there will be no Russian military experts in Turkey. So, other countries' demands not to use S-400 are unacceptable," the minister said, as quoted by TRT channel. 

Ankara signed a deal with Moscow to purchase its S-400 air-defence systems in 2017 and the first deliveries began in July 2019. The deal sparked a row between Ankara and Washington because Turkey also participated in the US F-35 programme and was waiting for delivery of its fighter jets. The US says Turkey won't be sent the aircraft unless it backtracks on the S-400 deal with Russia - Washington says that the Russian systems are incompatible with shared NATO defences and threaten its F-35s, while Ankara insists that the S-400s will operate independently from NATO defences. 

Last year, Turkish President Recep Tayyip Erdogan said that the country would continue testing the Russian air defence system. "America's stance is absolutely not binding for us...We aren't going to ask America," he said.