The U.S. has asked Turkey to postpone taking delivery of the Russian S-400 air defense systems until 2020, Reuters news agency reported. Speaking to the agency, a top-level Turkish official said, "We are going to receive the S-400s in July. Our position has not changed."

The most important part of meetings held with NATO Secretary-General Jens Stoltenberg, who visited Ankara last week, consisted of the same topic.

Ankara wanted to have a report written up through NATO that would relieve U.S. President Donald Trump with respect to S-400s, or strengthen his hand to take position in favor of Turkey. This would be a report stating that the S-400 system purchased by Turkey would not constitute a problem for NATO in the case that certain conditions are met (we can interpret this as the adaptation of the Identification of Friends or Foe to the NATO system).

I had mentioned last week in reference to a source who is right at the center of this process as per their position, but did not want to be named, that such a report would be requested from NATO.

I asked the same source about the new situation, or rather the current news: whether Washington's demand to postpone the purchase of S-400 missiles to 2020 is true, and if it is indeed true, how Ankara responded to this demand.

The source's response was: "They made us a written offer. But there is no new development with respect to postponing [the purchase]."

This is the only response we received to our question. So, we do not have many details - at least for now.

But even from these statements alone, we ascertain that the U.S. made a "written offer," possibly including the demand to postpone the purchase in order to make Turkey withdraw from the S-400 deal, and as "there are no new developments," Ankara is resisting this demand.

It is not difficult to guess that Russia will be the country most pleased from the S-400 issue turning into an unsolvable crisis between Turkey and the U.S.

We know that the Russians have certain political objectives behind the plan to sell these missiles to Turkey at affordable prices within the scope of a deal that will also meet all of Turkey's other demands. Moscow is acting strategically with the aim to have Ankara excluded from the NATO system.

Russian Ambassador to Ankara Aleksey Yerhov, who met with Parliament Chairman on Committee of Foreign Affairs Volkan Bozkır yesterday seemed to be making a call to "continue resisting."

Following the meeting the Russian ambassador told journalists, "President [Recep Tayyip] Erdoğan has clear statements regarding this matter. He said himself that the deal was signed. The Turkish press and Turkish public should trust and respect these extremely clear statements of the Turkish president."

The U.S. is threatening to not deliver the F-35 fighter jets in the case Turkey takes delivery of and implements the S-400 air system. They say Turkey cannot have both and that it must choose one.

Of course, it does not end here. It goes all the way to the U.S. threatening to impose sanctions on Turkey.

I had conveyed the information I received from military sources before.

Ankara was sent a "sanction list" through the U.S. Department of Defense that consists of more than 30 items, including the threat that F-16 parts would not be sent.

Meanwhile, Turkey is suggesting that, if the issue is based on certain technical question marks, a committee should be formed to discuss whether the S-400 missiles can access the NATO system or F-35s' secret information. This suggestion was voiced once more last week by Foreign Minister Mevlüt Çavuşoğlu. However, there are no signs that the other side is leaning toward this suggestion.

At a time when the S-400 issue is on the agenda with reports including the demand to postpone the purchase, news was received from Washington of a meeting that very clearly directly concerns the subject. The news in question is that Turkey's Ambassador to Washington Serdar Kılıç would meet with Undersecretary of the U.S. Department of State David Hale.

Could this appointment have emerged upon a new development? Or is it part of routine activity? Could Ambassador Kılıç have arranged this meeting to convey Turkey's response to the U.S. demand to postpone the S-400s to 2020?

Since our source in Ankara mentioned a "written offer," it becomes difficult to consider that the written suggestion includes a single clause. Perhaps a new negotiation process is starting upon the U.S.'s latest suggestion.

The topic will be further followed.