Gen. David Petraeus acknowledged Tuesday that "recent months in Afghanistan have seen tough fighting and tough casualties."

But "this was expected," he said. "The going inevitably gets tougher before it gets easier when a counterinsurgency operation tries to reverse insurgent momentum. My sense is that the tough fighting will continue. Indeed, it may get more intense in the next few months. As we take away the enemy's safe havens and reduce the enemy's freedom of action, the insurgents will fight back."