A Lockheed Martin F-35 aircraft is seen at the ILA Air Show in Berlin, Germany, April 25, 2018. Photo: Reuters / Axel Schmidt / File.

Turkey’s purchase of a Russian air defense missile system should not trigger US sanctions because Ankara is not an adversary of Washington and remains committed to the NATO alliance, Defense Minister Hulusi Akar said on Monday.

Speaking at a US-Turkey conference in Washington as tensions mount between the two NATO allies over Ankara’s plan to buy the Russian S-400 missile system, Akar adopted a relatively conciliatory tone and urged that issues be resolved through dialogue.

“Turkey is clearly not an adversary of the United States,” Akar said, adding that its procurement of the S-400 system should not therefore be considered within the scope of US sanctions designed to target America’s enemies.

US Secretary of State Mike Pompeo said last week that Washington had told Ankara it could face retribution for buying the S-400s under a sanctions law known as Countering America’s Adversaries Through Sanctions Act (CATSAA).

“This procurement decision does not signify a change in Turkey’s course. I’d like to reiterate strongly that there is no change in Turkey’s commitment to NATO,” Akar said.

The disagreement over the F-35 is the latest in a series of diplomatic disputes between the United States and Turkey including Turkish demands that Washington extradite cleric Fethullah Gulen, differences over Middle East policy and the war in Syria, and sanctions on Iran.

Turkish President Recep Tayyip Erdogan has refused to back down from Ankara’s planned purchase of a Russian S-400 missile defense system the United States has said would compromise the security of F-35 aircraft, made by Lockheed Martin Corp. Turkey has said it will take delivery of the S-400s in July.

In early April, the United States halted delivery of equipment related to the stealth F-35 fighter aircraft to Turkey, marking the first concrete US step to potentially blocking the delivery of the jet to Turkey.

Akar said Turkey was puzzled by the move and expected the United States and other partners in the program to fulfill their obligations.

“We firmly believe that linking the S-400 to the F-35 project is unfortunate. … We are one of the investors and partners and not just a buyer. We have invested over $1 billion … and fulfilled all our obligations,” he said.

Akar repeated Turkey’s offer to hold technical talks with the United States to address “technical concerns” over the S-400 purchase.

Turkey is also assessing a renewed offer from the United States to buy Patriot missile defense systems, Akar added. “Recently we received the restated offer for the Patriots. This offer is now on the table, we are studying it carefully.”

Speaking at the same conference, Erdogan adviser Ibrahim Kalin reiterated the wide range of issues on which Ankara and Washington work together in Syria and elsewhere in the Middle East and said any imposition of sanctions would dent that cooperation.

“Rather than using language of threats from sanctions against Turkey, I think the people here in Congress as well as this administration should understand Turkey’s security concerns,” he said.

The US Congress recently introduced several bipartisan resolutions targeting Turkey, calling on President Donald Trump’s administration to impose sanctions or prohibit the transfer of F-35 fighter aircraft.