ANKARA (Reuters) – Turkey and the United States are in talks over Washington’s offer to sell a Patriot missile defence system to Ankara, Turkey’s Foreign Minister Mevlut Cavusoglu said on Friday.

“The United States said they could sell Patriots, and the delegations are negotiating”, Cavusoglu was quoted as saying by news agency Anadolu.

Cavusoglu’s comments came after Bloomberg reported that Turkey had rejected a U.S. proposal to deliver a Patriot missile system by the end of the year.

During negotiations, the United States said it could deliver one system earlier, following Turkish objections to the delivery times, Cavusoglu said according to Anadolu. He added the possibility of joint production or a transfer of technology were also important for Ankara.

While offering the Patriots to Turkey, the United States has warned its NATO ally against buying a Russian missile defence system, saying it cannot be integrated into NATO air defences.

President Tayyip Erdogan has said Turkey remains committed to the deal for the Russian S-400 surface-to-air missile defence system.

“They (S-400s) will be delivered towards the end of this year in autumn. We bought S-400s because we could not purchase Patriots,” Cavusoglu said.

U.S. officials have said that if Turkey proceeds with the S-400 purchase, Washington would withdraw its offer to sell the $3.5 billion Raytheon Co missile package, and could block the sale of fighter jets to Turkey and impose sanctions.

Reporting by Ece Toksabay; Editing by Dominic Evans and Mark Potter