As reported by Censor.NET, he said in an interview to NBC.
Asked whether Russia was an ally in the renewed effort to get rid of ISIS out of Syria and Iraq, Carter said: "No, they haven't done anything against ISIL. Virtually zero. They came in, they said they were going to fight ISIL, and they said they were going to help in the civil war in Syria. They haven't done either of those things."
"And as a consequence, of course, we're fighting ISIL ourselves, we have a campaign plan that you see unfolded in Mosul today and Raqqa today, encouraged, that's going exactly according to the plan we laid out about a year ago. In fact, Iraqi security forces are approaching the Tigris River as we speak today," Carter stressed.
According to the U.S. Secretary of Defense, the Russian behavior in Syria certainly made the ending of the Syrian civil war harder.
"I think the Russians saw an opportunity there to play a role which could have been fine. Because what they said they were going to do, which they could uniquely do, is help Assad move aside gently, bring the moderate opposition into the Syrian government, and put an end to the terrible tragedy there. That's what they said they were going to do. That would have been okay. That's not what they've done. They've doubled down on the Syrian civil war," the Pentagon chief said.