Nuremberg Declaration on the Crime of Aggression of 8 May 2023: The International Nuremberg Principles Academy following on a thorough deliberation on these matters with leading international law experts adopted a declaration in which it:

“Calls upon the international community to support the establishment of a tribunal to
prosecute crimes of aggression as defined under international law committed on the
territory of Ukraine,

Calls upon States Parties to the Rome Statute of the International Criminal Court to amend the jurisdictional provisions governing the crime of aggression to align them with those applicable to the other crimes within the jurisdiction of the International Criminal Court.”

For the full declaration, see here.