The United States has called on Turkey to refrain from buying additional Russian arms after President Recep Tayyip Erdoğan said they still intended to acquire a new batch of Russian-made missile systems, despite Washington's opposition.

The move to buy a new round of S-400 air defense systems, which could deepen a rift between the two NATO allies, could trigger new U.S. sanctions, officials have said.

“Nobody will be able to interfere in terms of what kind of defense systems we acquire, from which country, at what level,” Erdoğan told CBS News correspondent Margaret Brennan in New York last week.

“We are the only ones to make such decisions,” the president said when asked if he intends to buy another round of S-400s.

When Brennan said, “that sounds like a yes,” Erdoğan answered, “Of course, of course, yes.”

“We urge Turkey at every level and opportunity not to retain the S-400 system and to refrain from purchasing any additional Russian military equipment,” a State Department spokesperson was cited as saying by Reuters when asked about Erdoğan’s comments Sunday.

“We continue to make clear to Turkey that any significant new Russian arms purchases would risk triggering CAATSA 231 sanctions separate from and in addition to those imposed in December 2020,” the spokesperson added, referring to the 2017 Countering America’s Adversaries Through Sanctions Act.

The spokesperson also said the United States regards Turkey as an ally and friend and seeks ways to strengthen their partnership “even when we disagree.”

Talks continued between Russia and Turkey about the delivery of a second batch and the two countries are in the process of signing a new deal in the near future, Alexander Mikheyev, the head of Russia’s state-run arms exporter Rosoboronexport, said in August.

Turkey’s initial purchase of the first batch of S-400s from Russia strained ties with the U.S.

The move prompted Washington to remove Turkey from the new generation F-35 Lightning II jet program, before it imposed sanctions on the country’s Defense Industry Presidency (SSB), its chief, Ismail Demir, and three other employees in December

The U.S. argued that the system could be used by Russia to covertly obtain classified details on the Lockheed Martin F-35 jets and that it is incompatible with NATO systems. Turkey, however, insists that the S-400 would not be integrated into NATO systems and would not pose a threat to the alliance.

Erdoğan explained that Turkey was not given the option to buy American-made Patriot missiles and that the U.S. had not delivered F-35 stealth fighter jets despite a payment of $1.4 billion (TL 12.37 billion).

Erdoğan is scheduled to meet Russian President Vladimir Putin Wednesday in Sochi, Russia.

“We will of course reach an important decision in Turkey-Russia relations,” Erdoğan said.