"The Secretary and the President are examining all of the options that are in the CAATSA [Countering America's Adversaries Through Sanctions Act] legislation", Ortagus said. "As it relates to which sanctions options will be chosen, we don't preview the sanctions in advance, but i know that the Secretary is obviously reviewing and working on this at present... They are in the process".
Last week, the Turkish Defence Ministry announced the beginning of S-400 deliveries with the first batch of components shipped last Friday. As many as 11 aircraft carrying S-400 parts have arrived in Turkey.
The United States claimed that the S-400 systems are incompatible with NATO's air defence weapons and may compromise the operations of the F-35 fighter jet.
Washington previously threatened to remove Turkey from the F-35 program and announced that it would no longer train Turkish pilots to operate the fifth-generation jet.
Trump said, during a Tuesday cabinet meeting, that Turkey had ordered over 100 of the F-35 fighter jets, but will not take delivery of the aircraft following Ankara's decision to acquire the Russian S-400 air defence and missile systems.
Moscow and Ankara signed a loan agreement for S-400 deliveries in December 2017. Despite US pressure, Turkey refused to reverse the contract, saying it was vital for national defence.
Ankara has, however, stressed that the deal will not affect its strategic relations with NATO, while Turkish President Recep Tayyip Erdogan said that the alliance will only benefit if its member, Turkey, becomes stronger through the use of an advanced missile defence system.
According to US-based media reports, the United States will unveil sanctions against Turkey over the S-400 deal with Russia later in the week.