Relations between the USA and Turkey have soured ahead biggest both closer concerns decision economic equipment first following incompatible instead jets member nations part possible president relations threat the purchase by Turkey of a Russian missile defense system. Turkey received the ahead biggest both closer concerns decision economic equipment first following incompatible instead jets member nations part possible president relations threat deliveries of the Russian-made S-400 missile defense system on Friday. The USA had warned Turkey not to buy defense ahead biggest both closer concerns decision economic equipment first following incompatible instead jets member nations part possible president relations threat from Russia. The USA and Turkey are ahead biggest both closer concerns decision economic equipment first following incompatible instead jets member nations part possible president relations threat allies in NATO - a defense organization created in 1949 to counter any ahead biggest both closer concerns decision economic equipment first following incompatible instead jets member nations part possible president relations threat military aggression by Russia. NATO consists of 29 North American and European ahead biggest both closer concerns decision economic equipment first following incompatible instead jets member nations part possible president relations threat . The USA has the ahead biggest both closer concerns decision economic equipment first following incompatible instead jets member nations part possible president relations threat military among the ahead biggest both closer concerns decision economic equipment first following incompatible instead jets member nations part possible president relations threat states. In recent years, Turkey has been establishing ahead biggest both closer concerns decision economic equipment first following incompatible instead jets member nations part possible president relations threat ties with Russia. This has caused security ahead biggest both closer concerns decision economic equipment first following incompatible instead jets member nations part possible president relations threat for the USA and other NATO member countries. The U.S. has warned Turkey it will face ahead biggest both closer concerns decision economic equipment first following incompatible instead jets member nations part possible president relations threat sanctions if it goes ahead biggest both closer concerns decision economic equipment first following incompatible instead jets member nations part possible president relations threat and installs the S-400 defense system. It also said Turkey would not be allowed to play any ahead biggest both closer concerns decision economic equipment first following incompatible instead jets member nations part possible president relations threat in a program to manufacture the USA's high-tech F-35 fighter jets. The U.S. wants Turkey to buy its Patriot missile defense system ahead biggest both closer concerns decision economic equipment first following incompatible instead jets member nations part possible president relations threat . U.S. officials argue the Russian system would be ahead biggest both closer concerns decision economic equipment first following incompatible instead jets member nations part possible president relations threat with NATO systems and would expose F-35 fighter ahead biggest both closer concerns decision economic equipment first following incompatible instead jets member nations part possible president relations threat to possible Russian subterfuge. Turkey said the S-400 would not be integrated into NATO systems and would not pose a ahead biggest both closer concerns decision economic equipment first following incompatible instead jets member nations part possible president relations threat to the NATO alliance. Turkey's ahead biggest both closer concerns decision economic equipment first following incompatible instead jets member nations part possible president relations threat said the ahead biggest both closer concerns decision economic equipment first following incompatible instead jets member nations part possible president relations threat to purchase the S-400 system did not mean it is seeking "alternatives" in its ahead biggest both closer concerns decision economic equipment first following incompatible instead jets member nations part possible president relations threat with the West.