Turkish President Recep Tayyip Erdogan has reaffirmed his country’s commitment to an agreement with Moscow to buy Russian S-400 missile defense systems, saying Ankara will not step back from the deal despite US threats of “devastating” consequences.

“There is a certain step that we took, there is an agreement here and we are committed to it,” Erdogan told reporters on Tuesday, adding that it was “out of the question for us to take a step back” from the deal the two countries finalized almost two years ago

Ankara decided in 2017 to purchase the Russian defense system following the failure of protracted efforts to buy air defense systems from the US.

A number of NATO member states have criticized Turkey for its planned purchase of the S-400, arguing the missile batteries are not compatible with those of the military alliance.

Last week, a top Pentagon official said the consequences would be “devastating” for Turkey’s joint F-35 fighter program and its cooperation with NATO if the country went ahead with plans to buy the Russian defense system.

Kathryn Wheelbarger, the acting US assistant secretary of defense for international security affairs, threatened that Washington would hit Turkey with sanctions if Ankara insisted on buying the Russian-made system.

US warns Turkey about consequences of buying S-400

A top Pentagon official has warned Turkey about devastating consequences of buying advanced Russian made S-400 air defense missile systems.

Erdogan said on Tuesday that Turkey had offered to set up groups with the United States to work together on the issue, without saying what Washington’s response had been.

He further said Turkey had also been discussing a US offer to sell Ankara Patriot missiles, saying, “However, unfortunately the US side has not given us an offer as good as the S-400s.”

“We can take a step for Patriots, if there is a positive offer as Russia made,” Erdogan said.

The Turkish president further said that a win-win approach would be in the interest of every country. “If it is not the case, we are not obliged to buy anything.”

US officials said they expect Ankara to opt for the American Patriot missiles instead rather than the Russian S-400 system from Moscow, arguing they would then allow the F-35 program to continue.

Turkey has responded by saying that it was the US refusal to sell it Patriots that led it to seek other sellers, adding that Russia had offered it a better deal, including technology transfers.