The United States will not lift sanctions on Turkey over its possession of Russia’s S-400 air defense system, the State Department signaled Wednesday, appearing to rebuff a suggestion by Turkey’s defense minister that the NATO allies could “find a solution” to the dispute.

“Our policy vis-a-vis the S-400 has not changed,” State Department spokesman Ned Price said Wednesday afternoon, adding, “We continue to urge Turkey not to retain the system.”

In an interview with Turkey’s Hurriyet newspaper on Tuesday, Defense Minister Hulusi Akar reiterated a proposal to discuss the S-400 dispute with US officials via a working group, adding that Ankara need not use the system “constantly,” likening his government’s possession of the Russian technology to Greece’s possession of the S-300.

Akar seemed to tie the S-400 issue to Washington’s support for the Syrian People’s Protection Units (YPG) in the fight against the Islamic State in Syria, saying the disagreement about the YPG could not be resolved without concession from Washington. Turkey considers the YPG to be inextricably linked to the Kurdistan Workers Party, designated as a terrorist organization by Ankara and its Western allies.