<p style="text-align: left;">Chemezov added that Russia had finished instructing Turkish specialists on the use of the S-400.</p> <p style="text-align: left;">Tensions between Turkey and the United States are running high over Ankara’s decision to buy the S-400 missile defenses, which are not compatible with NATO systems.</p> <p style="text-align: left;">Meanwhile the United States gave Turkey time until the 31th of July to backtrack on S-400 missile deal, media report citing Pentagon.</p> <p style="text-align: left;">Washington has reportedly given Ankara a chance to either abandon the S-400 deal with Russia until the end of the first week of June or face penalties, which would include sanctions, removal from Lockheed Martin's F-35 jet program and canceling the delivery of 100 F-35 jets, Sputnik news agency reported.</p> <p style="text-align: left;">Reporter’s code: 50101</p>