By Selcan Hacaoglu

Bloomberg News

ANKARA, Turkey — President Recep Tayyip Erdogan ruled out U.S. demands that Turkey delay the purchase of an advanced Russian missile-defense system, and said Moscow may bring forward the delivery date from July.

“It is definitely out of the question for us to step back on the issue of S-400s; it is a done deal,” Erdogan said in a televised speech in Istanbul late Saturday. “Our deal was to have the S-400s delivered to us by July; they will probably bring that forward.”

Erdogan’s stance could further strain ties between the NATO allies. The U.S. last week asked Ankara to delay taking the system to 2020, according to people familiar with the proposal. Pushing ahead with the deal carries a high risk of U.S. sanctions that could plunge Turkey into renewed economic turmoil.

The accord with Moscow highlights Turkey’s aspirations for an increasingly independent role in regional policies and the mutual erosion of trust with Washington.

“The S-400 is a defensive system and has a long range. As for the payment plan, Russia has given us very suitable conditions,” Erdogan said.

The proposed purchase has angered President Donald Trump’s administration, which argues that integrating such a system into NATO’s second-largest army could help Moscow gather critical intelligence on the stealth capabilities of the next generation F-35 fighter planes, which Turkish manufacturers help build. Erdogan dismissed the U.S. argument and said Turkish military experts were good at deciding what to purchase.