Related Rule
Uruguay
Practice Relating to Rule 137. Participation of Child Soldiers in Hostilities
Uruguay’s Law on Cooperation with the ICC (2006) states:
26.2. Persons and objects affected by the war crimes set out in the present provision are persons and objects which international law protects in international or internal armed conflict.
26.3. The following are war crimes:
34. … using [children under the age of eighteen years] to participate actively in hostilities. 
Uruguay, Law on Cooperation with the ICC, 2006, Article 26.2. and 26.3.34.
Upon ratification of the 1989 Convention on the Rights of the Child, Uruguay stated that “it will not authorize any persons under its jurisdiction who have not attained the age of 18 years to take a direct part in hostilities”. 
Uruguay, Declarations made upon ratification of the Convention on the Rights of the Child, 20 November 1990, reprinted in UN Doc. CRC/C/2/Rev.4, 28 July 1995, p. 32.
At the 27th International Conference of the Red Cross and Red Crescent in 1999, Uruguay pledged “to promote the adoption of national and international standards prohibiting the military … participation in armed conflicts of persons under 18 years of age”. 
Uruguay, Pledge made at the 27th International Conference of the Red Cross and Red Crescent, Geneva, 31 October–6 November 1999.
In 2003, in its second periodic report to the Committee on the Rights of the Child, Uruguay stated: “Article 13 of the new children’s code specifically provides that children and young people cannot participate in hostilities in armed conflicts or be trained for that purpose.” 
Uruguay, Second periodic report to the Committee on the Rights of the Child, 13 October 2006, UN Doc. CRC/C/URY/2, submitted 18 December 2003, § 327.