NEW : Attack is deadliest on U.S. forces in more than a year . Suicide bomber explodes truck at national police headquarters in Mosul . Five Americans among eight dead ; 60 others wounded . Score: 6
NEW : Attack is deadliest on U.S. forces in more than a year . Suicide bomber explodes truck at national police headquarters in Mosul . Five Americans among eight dead ; 60 others wounded . Mosul , 260 miles north of Baghdad , called last urban stronghold of al Qaeda in Iraq .