Turkey’s acquisition of the Russian S-400 air defence system will have grave consequences for the United States' defense relationship with Turkey, Pentagon Spokesperson Eric Pahon told Ahval in a written statement on Monday.

The United States government objects to the purchase on several grounds, with defence interoperability issues topping the agenda. U.S. officials and analysts also argue the Russian air defense system along with Russian officials who are almost certain to be stationed in Ankara would pose a significant risk to the new generation F-35s fighter jets set to be deployed in the country.

In an earlier report to the Congress in late November, the Pentagon said Turkey’s purchase of the Russian S-400 missile systems could result in Ankara’s exclusion from the programme to build and operate F-35 advanced fighter jets, as well as affecting its acquisition of other weapons including the Boeing Co.'s CH-47F Chinook helicopter and Lockheed’s F-16 fighter and UH-60 Black Hawk helicopters.

Pahon continued his statement, saying Washington understands Turkey’s desire to improve its air defense; however, "Turkey’s acquisition of the Russian S-400 air defense system will have grave consequences for the U.S. defense relationship with Turkey," he said.

Pahon in a statement said that the United States is "working to help Turkey find better solutions to address its defense needs while also warning of the broader implications of purchasing Russian S-400s."

U.S. President Donald Trump on Feb. 15 signed a spending bill that blocks the transfer of the country's F-35 new generation fighter jets to Turkey.

It is unknown yet whether this ban will include the other two F-35s already handed over to the Turkish government. Both jets remain in the United States, where Turkish pilots are receiving training.

Pahon said that the United States and Turkey have an open dialogue on this issue, adding that Washington had "emphasized the importance of maintaining NATO interoperability on any major defense systems procurements.‎"