The US Senate has castigated the State Department for failing to sanction Turkey over its purchase of Russian S-400 air defence systems.
The issue was raised at a hearing in the upper chamber of Congress on Tuesday. Deputy Assistant Secretary Matthew Palmer said that the State Department did not determine whether Turkey's acquisition of the Russian military hardware could be qualified as a violation of Countering America's Adversaries Through Sanctions Act (CAATSA).
Asked by one of the lawmakers behind the act if the purchase can be regarded as a 'substantial transaction', Palmer did not give a direct answer, noting that the issue is being examined at the moment.
Unsatisfied with the answer, the lawmaker said that if the S-400 purchase is not a substantial transaction, "then nothing is".
Washington earlier demanded that Ankara forego the deal and acquire US Patriot systems instead. Furthermore, the US excluded Turkey from the F-35 fighter jets programme over alleged concerns about the Russian systems sharing airspace with F-35 jets. However, Turkey says these worries are unfounded and insists that its intention to possess the S-400 will not change, nor will its decision to take part in the F-35 programme.