"This is not a threat or a bluff", Foreign Minister Mevlut Cavusoglu told broadcaster TGRT Haber, Reuters reported.
Turkey began taking delivery of parts of the S-400 earlier of this month despite strong objections from the United States, which says the systems are incompatible with North Atlantic Treaty Organisation and pose a threat to the US -led F-35 fighter jet program.
A USA official said it would cost some $500m to $600m to shift F-35 manufacturing from Turkey elsewhere.
The move comes after US State Department said last week that President Donald Trump and Secretary of State Mike Pompeo "are examining all of the options in the CAATSA [Countering America's Adversaries Through Sanctions Act] legislation over Turkey's purchase of Russian S-400 missile systems". A USA official said it would cost some $500 million to $600 million to shift F-35 manufacturing from Turkey.
Meanwhile, Russia and Turkey are in talks about the possibility of jointly manufacturing some components of Russia's S-400 missile defence system in Turkey, the TASS news agency cited Sergei Chemezov, head of Russia's Rostec state conglomerate, as saying.
Turkey's defense minister met with the U.S.' Syria envoy on Monday to discuss recent developments in Syria and establishing a safe zone there, the Defense Ministry announced.
According to the text, Akar told Jeffrey that Turkey feels irritated by high-level meetings of military and civilian USA officials with the leaders of YPG, which Turkey designates as a terrorist organization.
The U.S. -backed Kurdish People's Protection Units (YPG) militia controls much of northern and eastern Syria.
"If the safe zone is not established as planned and threats against our country continue, we will launch the military operation in the east of the Euphrates", he noted.
He repeated Turkish frustration that a deal with the United States for a YPG withdrawal from the town of Manbij had still not been implemented, more than a year after it was agreed.
He also said that only a a fully "democratic Turkey can and should be a strong ally for the USA and North Atlantic Treaty Organisation".