The top U.S. commander for the fight against the Islamic State group says he's skeptical of any additional military cooperation with Russia in Syria, and believes he can get the mission done without it.

Lt. Gen. Stephen Townsend says any decision to cooperate with Moscow is one for the administration to make. But "as a soldier, I'm fairly skeptical of the Russians," he said, adding he's not inclined "to believe the coalition can cooperate with them."

Townsend, who took command on Sunday, says he will accelerate military operations in Iraq, and expand the training and equipping of Iraqi forces. He says that will include giving combat training to Iraqi police, because they will face fighting as they try to maintain security in the cities once the militants are ousted.