ISTANBUL — Turkey has already bought S-400 defense systems from Russia and hopes they will be delivered in July, Turkish President Tayyip Erdogan said on Wednesday, an announcement likely to ratchet up tensions with Washington on the issue.

"Turkey has already bought S-400 defense systems. It is a done deal. I hope these systems will be delivered to our country next month," Erdogan said.

Turkey and the United States have sparred publicly for months over Ankara's order for the S-400s, which are not compatible with the NATO's systems.

US acting Secretary of Defense Patrick Shanahan outlined last week how Turkey would be pulled out of the F-35 fighter jet program unless Ankara changed course from its plans to purchase the S-400 missile defense system.

Speaking at a meeting of his AK Party members, Erdogan said Turkey will hold to account anyone who excludes Turkey from the F-35 program.

"We will hold to account Turkey's exclusion from F-35 program in every platform due to reasons without reason or legitimacy," Erdogan said. He noted that Turkey is also a manufacturing partner in the program.

Erdogan also said he wanted to talk about the issue on the phone with the United States, before he meets President Donald Trump in Osaka, Japan at the end of this month.

Erdogan, who is to meet Trump on the margins of G20 summit in Japan on June 28-29, said in a televised speech that before the gathering he "would like to discuss this issue by telephone and reverse it from the current situation back to where we started".

"We have so far paid $1.250 million," he said.

Turkey plans to buy 100 F-35s.

Russia said on Tuesday it plans to deliver its S-400s to Turkey in July, setting the clock ticking on a US threat to hit Ankara with sanctions if it goes ahead with the deal. — Agencies