Procuring Russian S-400 defense systems is a matter of national security for Turkey, the ruling party spokesman said Friday.
"Similarly, questioning Turkey on the F-35 program is like questioning NATO's joint projects and the collective concept of security," Ömer Çelik told reporters at the Justice and Development (AK) Party headquarters in Ankara.
Washington has balked at Turkey's purchase of the Russian S-400, and last week suspended delivery of parts and services for F-35 fighter jets.
U.S. officials have suggested Turkey buy the U.S. Patriot missile system rather than the S-400, arguing it is incompatible with NATO systems and would expose the F-35 to possible Russian subterfuge.
Turkey has responded that it was the U.S. refusal to sell it Patriots that led it to seek other sellers, adding that Russia offered it a better deal, including technology transfers.
"The U.S. should not turn its arms market competition into an issue of NATO alliance," Çelik added.
Speaking about the military coup in Sudan, he said Turkey expects the Sudanese people's demands for democracy to be fulfilled without dragging the country into civil war.
Following months of popular protest, President Omar al-Bashir, who has ruled Sudan since 1989, stepped down on Thursday, the country's army said.
