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Washington claimed it would trigger economic warfare on Ankara if Turkey went ahead with its deal to buy S-400 missiles from Moscow. The US, who recently sold 100 F-35 fighter jets to Turkey, see the S-400 missile systems as a threat and said Turkey could not have both at the same time. However, President Erdogan’s administration pledged to respond to any aggression with action of their own.

Foreign minister Mevlut Cavusoglu said: "If the United States takes any negative actions towards us, we will also take reciprocal steps. "We are determined on the S-400 issue. No matter what the results will be, we will not take a step back.” The minister added that it is impossible to cancel the order from Russia.

Erdogan wishes to buy Russia's S-400 missiles by July

The missiles are seen as incompatible with NATO by the US

As well as threatening sanctions, Washington sent a letter yesterday saying it would pull Ankara out of the F-35 jet programme – despite being a fellow NATO member. The minister continued: “We reject the wording [of] the letter [by acting Defence Secretary Patrick Shanahan] to our defence minister. “Nobody can give an ultimatum to Turkey.” His words were echoed by Russia’s ambassador to Turkey, who said: “There is no change and there will be no change.”

The US Defence Secretary threatened earlier this month to remove all Turkish pilots currently training in the US if the deal went ahead – but it failed to deter President Erdogan. The US is concerned that any F-35s they sell could be exposed to subterfuge by the Russians. In addition, the Russian system is allegedly incompatible with NATO systems. Mr Cavusoglu's aggressive speech ensured the Turkish lira weakened 1.5 percent in a single day. The threat of sanctions has spooked investors over the past year, causing a huge lira sell-off.

Erdogan and Putin have enjoyed warm relations recently

The S-400 missiles in question

Washington are also offering the carrot as well as the stick as they desperately seek to get Turkey on board. They are reportedly discounting their own missiles and have offered to protect the Turkish economy should Russia respond to their severing of ties. Assistant Defence Secretary Kathryn Wheelbarger said: “We would be seeking ways to protect the Turkish economy from any potential blowback – Turkey is learning perhaps the hard way that Russia cannot be relied upon.”

It also ties into the overall power struggle in the region as both Russia and the US scramble to get nations on side.

Turkey has played a curious role in this – especially in Syria. President Erdogan initially expressed a desire to overthrow President Assad – aligning with US interests – but has recently brokered a deal with Iran and Russia around the Idlib situation. Turkey decided to buy the missiles in 2017 amid Washington urging them to purchase the US Patriot system instead. The US has had other issues with nations wishing to buy the Russian missiles systems, too.

Trump and Putin have met before, but relations have been mixed

Erdogan has even met with Rouhani, courtesy of Russia