Six car bombs explode in Iraq , Baghdad 's Mehdi Army says . Separate roadside bombing south of Baghdad kills Six civilians , official says . A woman reportedly was injured by shrapnel from the grenade , but was treated and released , he said . U.S. , Sunni troops ambushed in northern Iraq ; two attackers killed , U.S. military says .
Six car bombs explode in Iraq , Baghdad 's Mehdi Army says . Separate roadside bombing south of Baghdad kills Six civilians , official says . U.S. , Sunni troops ambushed in northern Iraq ; two attackers killed , U.S. military says .