The Pentagon will not entertain Turkey’s plan to set up a bilateral working group aimed at tempering US fears over the looming acquisition of Russian air defenses, the Defense Department told Al-Monitor today.

Speaking at a Washington panel celebrating the 70th anniversary of the NATO alliance on Wednesday, Turkish Foreign Minister Mevlut Cavusoglu again insisted that the purchase of the Russian made S-400 was “a done deal.” But he also floated the idea of creating a bilateral panel to try to quell US fears that the system could give Russia insights into Western weapons systems, including the F-35 fighter jet, for which Turkey builds the fuselage.

Cavusoglu’s pitch for a working group appears to be the newest idea from Ankara to quash tensions over the pending purchase of the S-400, which Turkey insists will not be integrated into NATO networks. But the Donald Trump administration isn’t interested.

“A technical working group at this stage isn't necessary or a path the US is even considering as a resolution,” said Pentagon spokesman Eric Pahon. “We have been clear with Turkey at all levels — the S-400 is a threat to the F-35 program and the safety of our NATO allies.”