Соответствующая норма
Practice Relating to Rule 7. The Principle of Distinction between Civilian Objects and Military Objectives
Section D. Attacks against places of civilian concentration, including schools
Uruguay’s Military Penal Code (1943), as amended, punishes anyone who carries out “an unjustified attack against … schools”. 
Uruguay, Military Penal Code, 1943, as amended, Article 58(12).