Washington is alarmed about the S-400 surface-to-air missiles (SAMs) deal between Moscow and Ankara, US Permanent Ambassador to NATO Kay Bailey Hutchison told a news briefing on Tuesday, Bloomberg reported.

“Our government is firmly in the camp of looking for an opportunity to have an arms control agreement that would include all the countries that have these intermediate ballistic missiles,” U.S. Ambassador to NATO Kay Bailey Hutchison said during a Tuesday call with reporters, a day before the alliance’s defense ministers meet in Brussels.

"Now America is going forward with the treaty protocol to give notice that we need to begin to develop a defense to the violating missiles that Russia has been developing".

“We are very concerned about any kind of Russian missile defense in one of our alliance countries,” Hutchison said. “The whole alliance is concerned about this and we hope that Turkey will make the right decision and look for another system.”