Protocol III on Prohibitions or Restrictions on the Use of Incendiary Weapons prohibits, in all circumstances, making the civilian population as such, individual civilians or civilian objects, the object of attack by any weapon or munition which is primarily designed to set fire to objects or to cause burn injury to persons through the action of flame, heat or a combination thereof, produced by a chemical reaction of a substance delivered on the target. The protocol also prohibits the use of air-delivered incendiary weapons against military targets within a concentration of civilians, and limits the use of incendiary weapons delivered by other means. Forest and other plants may not be a target unless they are used to conceal combatants or other military objectives.[1][9] Protocol III lists certain munition types like smoke shells which only have a secondary or additional incendiary effect; these munition types are not considered to be incendiary weapons.[10]