Règle correspondante
Practice Relating to Rule 37. Open Towns and Non-Defended Localities
Section C. Attacks on open towns and non-defended localities
Mexico’s Army and Air Force Manual (2009) states: “It is prohibited to: … attack or bombard cities, towns, villages, dwellings or buildings which are inhabited and undefended.” 
Mexico, Manual de Derecho Internacional Humanitario para el Ejército y la Fuerza Área Mexicanos, Ministry of National Defence, June 2009, § 389(D).