The Turkish defence ministry said in a statement "the wording and approach" of a letter sent early this month by Acting US Defense Secretary Patrick Shanahan "was not in the spirit of an alliance (and) caused unease".
Turkey Says US Ultimatum Over S-400 'Not in Spirit of Alliance'
STEPANAKERT, JUNE 18, ARTSAKHPRESS: The ministry said Turkey's previously "known" opinions on acquiring the Russian S-400 missile defence system had been shared in a detailed manner, without offering further information, France24 reports.
Shanahan's letter warned Ankara has until July 31 to renounce the S-400 purchase or Turkish pilots would be booted from US training on America's latest-generation F-35 fighter jets.