The United States has sanctioned Turkey over its purchase of Russian S-400 air defence systems, a long-anticipated reprimand that Ankara criticised as incompatible with the alliance between the Nato members.
"The United States made clear to Turkey at the highest levels and on numerous occasions that its purchase of the S-400 system would endanger the security of US military technology and personnel and provide substantial funds to Russia’s defence sector," US Secretary of State Mike Pompeo said on Monday.
“We will not tolerate significant transactions with Russia's defence sector,” he added.
Turkey’s foreign ministry condemned the move, calling on the US to "turn back from this grave mistake".
"Turkey is ready to tackle the issue through dialogue and diplomacy in a manner worthy of the spirit of alliance," it said in a statement.
The sanctions "will inevitably negatively impact our relations, and (Turkey) will retaliate in a manner and time it sees appropriate," the ministry added.
Turkey acquired the missile system from Moscow in 2019 despite warnings from US officials that the system was a threat to Nato security and incompatible with the alliance’s equipment.
Ankara says the Russian system was purchased after the US refused to sell it Patriot missiles and points out that Russian S-300 systems are used by Nato members Bulgaria, Greece and Slovakia. Turkey insists that its use of the system poses no threat to F-35 fighter jets and other shared defences and would not be connected to Nato systems.
In spite of these assurances, the US responded by removing Turkey from its F-35 programme.
“The F-35 cannot coexist with a Russian intelligence collection platform that will be used to learn about its advanced capabilities,” the White House said last July.
“Accepting the S-400 undermines the commitments all Nato Allies made to each other to move away from Russian systems," the statement continued.
Monday’s sanctions were announced under the Countering America's Adversaries Through Sanctions Act, the first time the 2017 law aimed at pushing back at Russia has been used against a Nato ally.
The sanctions target Turkey's top defence procurement and development body Presidency of Defence Industries (SSB), its chairman Ismail Demir and three other employees.
The sanctions block most export licenses to the SSB, bar the four targeted individuals from entering the US and freeze any of their assets there.
The SSB is tasked with reducing Turkey’s dependency on foreign defence products, a strategy developed in response to previous US actions towards Ankara.
In 1964, then-US President Lyndon Johnson warned Turkish Prime Minister Ismet Inonu against US-supplied military equipment in Cyprus. When Turkey invaded the Mediterranean island in 1974, Congress responded by imposing an arms embargo on Ankara for three-and-a-half years, an action which spurred the development of Turkey’s domestic defence industry.
In recent years, US reluctance to sell Turkey armed drones for use against the Kurdistan Workers’ Party led Turkey to develop its own weaponised unmanned aircraft, which have since played decisive roles in conflicts in Syria, Libya and Nagorno-Karabakh.
Russian Foreign Minister Sergei Lavrov said the sanctions were evidence of American “arrogance” that would hurt US standing internationally.