WASHINGTON - Turkey could still get hit with U.S. sanctions, part of the continuing fallout over its decision to accept delivery of Russia’s S-400 air defense system in July.



“They are not out of the woods on imposition of sanctions," State Department Assistant Secretary for Political-Military Affairs R. Clarke Cooper told reporters in Washington Thursday.



"All the options are on the table," he said, adding Washington has no timeline for making a decision.

R. Clarke Cooper, Assistant Secretary of State for Political-Military Affairs, is seen in an official State Department photo.

Tensions between Turkey, a key U.S. and NATO ally, and Washington have been growing over the past year, sparked in part by U.S support for some Kurdish forces in Syria in the fight against the Islamic State terror group. But Ankara’s decision to go ahead with purchase of the advanced, Russian-made air defense system has been equally thorny.



For months, the U.S. had warned Ankara that by accepting the S-400, it was jeopardizing its relationship and risked losing its role as a key partner in the production of the F-35 joint strike fighter, the most advanced in the U.S. fleet.



Following Russia’s July delivery of the S-400, the White House announced the F-35 partnership with Turkey was over, costing Turkish companies an estimated $9 billion.



“Turkey’s decision to purchase Russian S-400 air defense systems renders its continued involvement with the F-35 impossible,” the White House said in a statement at the time, describing the S-400 as a “Russian intelligence collection platform that will be used to learn about its advanced capabilities.”



“Accepting the S-400 undermines the commitments all NATO Allies made to each other to move away from Russian systems,” the White House added.



On Thursday, Cooper said some of the penalties Turkey faces are mandated by law, including some that could be levied under the Countering America’s Adversaries Through Sanctions Act (CAATSA).



But he said other factors were also at play.



“Turkey’s an Interesting case because we have a number of partners where we have growing relationships with who are closely watching how Turkey is managed,” Cooper said.



But he also expressed some hope that relations between the U.S. and Turkey could be repaired.



"Depending on who one talks to in the Turkish government, there are those who are acutely aware and sensitive and appreciative that this is not over and are wanting to get back to how things may have been" Cooper added. "Decisions coming out of Ankara are not necessarily reflective of the military institution or the foreign ministry."



Separately, Cooper said the recent approved sale of 32 F-35 fighters to Poland for $6.5 billion was unrelated to the decision to oust Turkey from the program.



"The Poland purchase was well within the works way before we had to impose a break with Turkey,” he said.