ISTANBUL (Reuters) - Turkey said on Tuesday a U.S. warning that Ankara would be removed from Washington's F-35 fighter jet program unless it drops a planned purchase of a Russian air defense system was out of keeping with the spirit of NATO partnership.
A letter sent by U.S. acting Secretary of Defense Pat Shanahan to his Turkish counterpart earlier this month warning of the F-35 cancellation, and Ankara's insistence on installing the Russian S-400 system, has stoked tensions between the NATO allies.
Ankara has condemned the letter, saying it will not back down from its decision to acquire the S-400 missiles, which Turkish President Tayyip Erdogan on Saturday said would arrive in Turkey in the first half of July.
On Tuesday, Turkish Defence Minister Hulusi Akar wrote back to Shanahan, his ministry said. "The letter repeated Turkey's discomfort over the tone and approach which does not fit the spirit of (NATO) allies and conveyed in detail our known opinion on the issue," it said in a statement.
Akar also underscored the importance of continuing dialogue in pursuit of solutions to problems, it added.
The United States says Turkey's acquisition of the Russian system poses a threat to Lockheed Martin Corp's F-35 stealth fighters. It has threatened to impose sanctions on Ankara under its Countering America's Adversaries Through Sanctions Act (CAATSA), the possibility of which has spooked investors and caused a selloff in the lira this year.
Ankara says it is not an enemy of the United States and therefore should not be subject to such sanctions. Erdogan said he would discuss the issue with U.S. President Donald Trump when they meet at this month's G-20 summit.
Turkey, a manufacturing partner in the F-35 program, has also proposed that the allies form a working group to assess the impact of the S-400s, but Washington has been cool to the idea.
(Reporting by Ezgi Erkoyun; Editing by Humeyra Pamuk and Mark Heinrich)