"Thanks to skillful leadership of our president, a PKK state, which was tried to be established on Turkish-Syrian border, is out of question now," Ibrahim Kalin said after a Cabinet meeting in capital Ankara.

According to Anadolu news agency Kalin said the government in Syria is carrying out attacks to provoke Turkey and take lands.

"Our related units are authorized to stop these attacks and contacts were established especially with Russia [in this regard]. The talks are going on," he added.

Speaking about the U.S. acting defense secretary’s letter to Turkey's defense chief, Kalin said the letter is "against the spirit of alliance" and an "appropriate" response will be given.

The presidential spokesman said he has discussed the letter with U.S. National Security Adviser John Bolton.

The letter sent last week said that Washington was cutting short a F-35 fighter jet training program for Turkish pilots over "safety concerns."

Kalin said the U.S.’s attitude on Ankara’s purchase of Russian S-400 air missile system “would permanently harm bilateral relations” and expressed hope that the U.S. would give up this attitude.

"The F-35s, which are Turkey's right, will definitely come to our country," he added.

Delaying this process and trying to distract it with different reasons will "only" harm the process and the bilateral relations, Kalin added.

Washington claims the S-400 purchase will jeopardize Turkey's role in the F-35 fighter jet program and has threatened sanctions.

Turkey has said there is no conflict between the S-400 and the F-35 and has called for a working group to clarify the issue.

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