United States Ambassador to NATO Kay Bailey Hutchison walks to the podium prior to a media conference at NATO headquarters in Brussels, Tuesday, June 25, 2019. (AP Photo/Virginia Mayo)

BRUSSELS (AP) — The U.S. envoy to NATO said Tuesday that Turkey will be axed from the high-tech F-35 fighter jet program if it goes ahead with plans to buy Russian S-400 air defense missiles.

U.S. Ambassador Kay Bailey Hutchison said "there will be a disassociation with the F-35" if NATO member Turkey buys the Russian missile system, as President Recep Tayyip Erdogan has vowed to do.

Speaking on the eve of NATO talks in Brussels, Hutchison said "we cannot have the F-35 in any way affected by, or destabilized by, having this Russian system."

The United States and other NATO allies have repeatedly complained about the purchase, saying the S-400 is not compatible with other allied systems and represents a security threat, particularly to the F-35.

But Hutchison said Turkey does not appear ready "to retract on the sale."

Indeed, Erdogan repeated Tuesday that Turkey had no intention of doing so.

"Turkey does not negotiate, seek permission or bow to pressure from other countries on the issue of meeting its security needs," the Turkish leader told his ruling party's legislators.

"The S-400 issue is directly related to our sovereign rights, and we will not step back (from this decision)," he said.

Erdogan also reiterated that Turkey was expected to take delivery of the Russian system next month.

Turkey's President Recep Tayyip Erdogan addresses his ruling party MPs, in Ankara, Turkey, Tuesday, June 25, 2019, two days after Ekrem Imamoglu, the candidate of the secular opposition Republican People's Party won the election for mayor of Istanbul. Erdogan addressed his AK Party's weekly meeting, the first time he speaks since the Istanbul mayoral election Sunday, which was a big setback for him and his party.(AP Photo/Burhan Ozbilici)
United States Ambassador to NATO Kay Bailey Hutchison walks to the podium prior to a media conference at NATO headquarters in Brussels, Tuesday, June 25, 2019. (AP Photo/Virginia Mayo)
United States Ambassador to NATO Kay Bailey Hutchison walks to the podium prior to a media conference at NATO headquarters in Brussels, Tuesday, June 25, 2019. (AP Photo/Virginia Mayo)