"We reject the premise that the Turkish government is in league with Daesh/ISIL to smuggle oil. We have seen no evidence to support such an accusation," the official said. "Moreover, Turkey is taking steps to improve the security of its border with Syria, working with international partners. One goal of this effort is to cut off Daesh smuggling."
Comment: It's difficult to see something you refuse to look at. "Seeing no evidence" does not mean that no such evidence exists: Russian Defense Ministry presents evidence of Turkey's role in ISIS' oil trade
Russian Deputy Defense Minister Anatoly Antonov stated earlier on Wednesday that Turkish President Recep Tayyip Erdogan and his family are involved in the illegal deliveries of oil from the IS, whose activities are prohibited in Russia.
Comment: The US probably knows the evidence is clear but desperately wants to keep Turkey in the great game.