Turkey’s suspected test firing of a Russian made S-400 air defense missile on the 16th triggered strong dissatisfaction from the United States, demanding that Turkey abandon the deployment of this Russian developed weapon system, or it may impose sanctions. < / P > < p > a video shows that a missile was launched off the coast of Turkey’s Black Sea on the 16th, leaving a thin curly trail of smoke in the blue sky. The video is believed to have been shot in the Turkish port city of Sinop. Multiple sources have previously said that the Turkish military will test the S-400 system there, and the airspace and waters nearby have been controlled. A U.S. official, who asked not to be named, told Reuters that earthwork was testing the S-400 system. The official did not provide further details. Military expert Turan owuz also believes that the color, density, angle and trajectory of the smoke in the video match the S-400 missile, and the angle of the trajectory shows that the target of the missile is “not particularly high.”. < / P > < p > Turkey signed a US $2.5 billion contract with Russia in 2017 to purchase the first S-400 air defense system, which will be delivered by Russia in 2019. The two sides signed a contract again in August this year to purchase the second batch of S-400 systems. As a member of North Atlantic Treaty Organization (NATO), Turkey’s purchase decision was opposed by the United States and NATO. The US side said that the Russian made S-400 system is not compatible with NATO air defense system and may help Russia track the F-35 stealth fighter developed by the United States and its allies. In July 2019, the US side suspended the qualification of earthwork to participate in the F-35 project. With regard to Turkey’s suspected test firing of S-400 system missiles, US State Department spokesman Morgan altags said on the 16th that the United States had previously expressed dissatisfaction with the “highest level” of the Turkish government and “could not accept” Turkey’s purchase of S-400 and other Russian weapon systems. < / P > < p > “if confirmed, we will condemn the test firing of the S-400 missile in the strongest possible way,” ortags said in a statement. “This is in conflict with Turkey’s responsibility as a member of NATO and a strategic partner of the United States.” The U.S. Department of Defense said in a separate statement that Turkey should not “activate” the S-400 system, which hinders the development of bilateral relations between the United States and Turkey. Jim Risch, chairman of the Foreign Relations Committee of the U.S. Senate, warned that this is an “unacceptable act” and poses a “direct threat” to the F-35 and other U.S. and NATO weapon systems, and that sanctions should be considered to send a “strong signal.”. On the 16th, the Turkish Ministry of defense did not respond to the test firing report. However, Turkish President Recep Tayyip Erdogan and several Turkish officials have repeatedly reiterated that they will not stop buying S-400. < / P > < p > in order to urge Turkey to give up the S-400, the US side has repeatedly called on Turkey to purchase the US made “Patriot” air defense missile system. However, the price of “Patriot” is higher than that of S-400, and Turkey has repeatedly complained that the price of weapon system in western countries is too high.