WASHINGTON — The U.S. has begun using Apache AH-64 attack helicopters to strike at ISIS targets inside Iraq, the first time the aircraft have been used for offensive strikes since arriving in Baghdad in early July. Their use opens up a new capability in the airstrike campaign against ISIS in Iraq, but one that also comes with risks, as they could be vulnerable to ground fire. A defense official confirms that Apache helicopters were used this weekend as part of four airstrikes on a large ISIS force northeast of Fallujah. The attack was conducted in coordination with Air Force fighter...