Related Rule
Practice Relating to Rule 161. International Cooperation in Criminal Proceedings
Section A. Cooperation between States
Ukraine’s IHL Manual (2004) states:
In case of serious violations of international humanitarian law, parties to the armed conflict shall take measures individually and jointly, as well as in cooperation with the United Nations according to the Charter of the United Nations. 
Ukraine, Manual on the Application of IHL Rules, Ministry of Defence, 11 September 2004, § 1.8.9.