Washington warns Ankara: You can't buy both Russian and American weapons

Turkey is on the receiving end of a bit of jealousy from its American partners. Washington has sent a formal notification to Ankara informing them that if they purchase Russia’s S-400 surface-to-air missiles, that the U.S. will not sell the Turks American F-35 jets.
This isn’t the only such instance of Washington throwing its weight around when it comes to telling other countries that they can’t purchase military hardware from the Russians. Already this year, a statement was made that if Iraq was to make such a purchase of Russia’s S-400 systems, sanctions would be imposed. Washington’s friendly notice was reported by ekathimerini:

Washington has given Ankara an ultimatum as regards the latter’s decision to buy Russian S-400 surface-to-air missiles worth 2.5 billion dollars, according to Turkish newspaper Hurriyet.
If Ankara proceeds with the sale, it will not receive 5th generation F-35 stealth fighters from the US, according to the Turkish newspaper.
The same report refers to a new deal between Turkey and the USA for the purchase of  Patriot anti-aircraft systems with Turkish Foreign Ministry spokesman Hami Aksoy being quoted as saying that “discussions” about the Patriot systems were continuing.
The report adds that Turkey is considering the purchase of air defense systems form the French-Italian consortium Eurosam.
The ministry spokesman admits that the system being purchased from Russia is not compatible with NATO systems but that Turkey’s goal is to develop a system that is compatible with NATO.

Apparently, American military products come with strings attached. On the part of Washington, the reason, of course, for this threat is that America’s hope is to financially damage Russia’s military business, as the American military industrial complex doesn’t like competition, and wishes to hold a monopoly status with its customers.
Not only is this a move to eliminate competition, since Washington has deemed Russia a threat, any move to isolate them, in any sector, is a good move. In this case, Washington hopes to prevent the Russians from securing a military deal worth $2.5 billion, so that this is just that much less that the Russians will receive, and one less customer for the Russian military hardware industry.
Editor’s addendum: Of course, what is of direct relevance here to Greece and Cyprus is the outcome of this potential geopolitical realignment in the region. As Greece is a NATO member, a falling out between Turkey and Washington may bolster Greece’s relative position within the alliance.
At the same time, Greece and Russia are traditionally close, and recently, Greece and Cyprus were among the countries which refused to expel Russian diplomats over the Skripal case, while they also opposed stricter EU measures against Russia. Turkey, however, has been forging closer ties with Russia in the past year-plus.