The conduct of hostilities in urban areas is inherently difficult, particularly with respect to the protection of civilians. International humanitarian law places restraints on both attackers and defenders. While much is written about the obligations of attackers with respect to protecting civilians, much less attention has been paid to the defender's obligations. These obligations are routinely referred to as "passive precautions" or "precautions against the effects of attacks" and are codified in Article 58 of Additional Protocol I to the 1949 Geneva Conventions. Article 58 requires parties, "to the maximum extent feasible", to remove civilians and civilian objects from the vicinity of military objectives, to avoid locating military objectives within or near densely populated areas, and to take other necessary precautions to protect civilians and civilian objects from the dangers resulting from military operations.