Turkey on Sunday dismissed US threats of sanctions if it went ahead with a Russian missile purchase, saying it would not renege on a pledge to Moscow, AFP reported.
Turkey’s deal with Russia to purchase the S-400 air defense missile system has caused tensions between Washington and Ankara.
The US believes the S-400 sale is part of Russian efforts to disrupt the alliance amid Western concern over Erdogan's burgeoning relationship with Russian President Vladimir Putin.
US officials said last month that Washington had stopped delivery of F-35 fighter jet parts to Turkey in response to Ankara's decision to move ahead with the purchase of the Russian surface-to-air missile system.
Turkish officials insist that the deal to purchase the S-400 does not affect the security of the US and have stressed that they will go ahead with the deal despite Washington’s objections.
"The US threats of sanctions shows that they don't know Turkey," Vice President Fuat Oktay told Kanal 7 television on Sunday.
"The decision on the S-400 has been taken. Once a pact has been signed, one's word given, Turkey respects it," he added.
Turkey has said it will take delivery of the S-400s in July though President Recep Tayyip Erdogan recently suggested that the delivery could be earlier than initially planned.