The long-anticipated step, which is likely to infuriate Ankara and severely complicate relations with the incoming administration of President-elect Joe Biden, could be announced any day, sources said.

The sanctions would target Turkey’s Presidency of Defense Industries and its head, Ismail Demir, sources have said. Several sources said they were expecting the announcement on Friday but one said it could come any day.

The Turkish lira weakened following the news. US sanctions could harm a Turkish economy already struggling with a coronavirus-induced slowdown, double-digit inflation and badly depleted foreign reserves.

A senior Turkish official said sanctions would backfire and hurt ties between the two NATO members.

“Sanctions would not achieve a result but be counter-productive. They would harm relations,” the official said.

“Turkey is in favor of solving these problems with diplomacy and negotiations. We won’t accept one-sided impositions,” he said.

To be sure, the US State Department could alter its plans and widen or narrow the scope of planned sanctions against Turkey, a NATO ally for decades.

However, sources said the announcement of the sanctions in their current form was imminent and suggested the United States -- after long waiting for Turkey to change course in the face of US warnings about sanctions requirements under the law -- was out of patience and finally ready to act.

The Pentagon referred questions on any potential sanctions to the State Department. The State Department did not immediately respond to a request for comment.

Russia delivered the ground-to-air S-400s last year and Turkey tested them as recently as October. Ankara said they would not be integrated into NATO systems and pose no threat, and has called for a joint working group on the issue.

But the United States has stressed that the S-400 poses a threat regardless, and went so far as to announce last year that it was removing Turkey from the F-35 fighter jet program over Ankara’s decision.

Lockheed Martin’s F-35 stealth fighter jet is the most advanced aircraft in the US arsenal and is used by NATO members and other US allies.

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