Related Rule
Practice Relating to Rule 71. Weapons That Are by Nature Indiscriminate
Colombia’s Basic Military Manual (1995) states that the use of weapons which “cause unnecessary and indiscriminate, extensive, lasting and serious damage to people and the environment” is prohibited. 
Colombia, Derecho Internacional Humanitario – Manual Básico para las Personerías y las Fuerzas Armadas de Colombia, Ministerio de Defensa Nacional, 1995, pp. 49-50; see also p. 30.
In 2007, in the Constitutional Case No. C-291/07, the Plenary Chamber of Colombia’s Constitutional Court stated:
The principle of distinction is complex and encompasses a number of treaty and customary norms applicable in internal armed conflicts, in addition to, in many cases, enjoying ius cogens status. These rules [include] … the prohibition against … the use of weapons that have indiscriminate effects. 
Colombia, Constitutional Court, Constitutional Case No. C-291/07, Judgment of 25 April 2007, pp. 84–86; see also pp. 94 and 95.