Turkish President Recep Tayyip Erdogan says he hopes to persuade the United States to back off its threat to exclude his country from the F-35 fighter jet program as punishment for Ankara's decision to buy a Russian missile-defense system.

Erdogan on June 12 said he "would like to discuss this issue by telephone and reverse it from the current situation back to where we started.'

Erdogan is scheduled to meet with President Donald Trump on the margins of Group of 20 summit in Japan on June 28-29, but the Turkish leader said he will speak to the U.S. president by phone on June 13.

The United States has given Turkey a deadline of July 31 to reverse its purchase of the Russian-made S-400 missile-defense system or face the loss of subcontracting work on the U.S.-led F-35 fighter jet project. Ankara also plans to buy 100 of the jets for its own military's use.

Acting U.S. Defense Secretary Patrick Shanahan sent a letter to his Turkish counterpart that explained the measures to remove Turkey from the program unless Ankara changes course.

Washington and its allies consider the missile system to be incompatible with NATO systems and a threat to the F-35 fighter jets.

Russia on June 11 said it plans to deliver its S-400 missile defense systems to Turkey in July.

Erdogan has resisted U.S. pressure to back out of the Russian purchase, saying it is a done deal and has dismissed suggestions it is a threat to NATO systems.

Erdogan, in a June 12 television address, vowed to seek answers from Washington on his country's 'exclusion from F-35 project for reasons that have no rational or legitimate basis.'

'Look, I am not saying Turkey will buy the S-400 defense system -- I say Turkey has bought it,' he said.

'We have completed the business. God willing, the system will be delivered to our country next month,' he added.

Washington has suggested that Ankara instead purchase the U.S.-made Patriot air defense system.

But Erdogan said Russia offered a better deal on pricing and joint production work.

'This is not an attack system but a defense system. Won't we take necessary measures to defend our country?' he said.

'Did we ask for such a defense system from America? Yes, we did. Did they deliver? No, they didn't,' he said.

Defense chief Shanahan last week said the U.S. offer for the Patriots was 'very competitive.'

With reporting by AFP, dpa, and Reuters

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