As a friend of mine said about war. The enemy is any one who stands and watches you, or who walks along as is nothing is happening, or runs away. Shoot them it is easier to ask forgiveness than ask permission.
Not to be cruel, but for at least 60 years (since Hiroshima) there have not been civilians. Everyone lives on the battlefield. The Islamists understand this, and have no problem with targeting 'civilians'. I do not necessarily advocate targeting non-combatants, but I do not think that we should twists ourselves in knots avoiding them. At some point, we have to destroy what they love.