Practice Relating to Rule 20. Advance Warning
In 2007, in the Constitutional Case No. C-291/07, the Plenary Chamber of Colombia’s Constitutional Court stated:
The precautionary principle is the cornerstone of a number of specific rules which are considered to have attained customary status and to be applicable in internal armed conflicts … Among these rules is … the obligation of the parties to a conflict to give effective advance warning of attacks which may affect the civilian population, unless circumstances do not permit.
[footnote in original omitted]