Russia faces "difficult fight" to retake Ukraine-held area, says top US spy

"We can be certain that Putin will mount a counteroffensive to try to reclaim that territory," Cohen said. "I think our expectation is that that will be a difficult fight for the Russians."

Putin, he said, "is not only going to have to face the fact that there is a front line now within Russian territory that he's going to have to deal with, he has to deal with reverberations back in his own society that they have lost a piece of Russian territory."