International criminal law is the body of law that prohibits certain categories of conduct deemed to be serious crimes, regulates procedures governing investigation, prosecution and punishment of those categories of conduct, and holds perpetrators individually accountable for their commission. The repression of serious violations of international humanitarian law is essential for ensuring respect for this branch of law, particularly in view of the gravity of certain violations, qualified as war crimes. It is in the interest of the international community as a whole to investigate and repress such crimes. There are several basic principles upon which international criminal law is based. Since international crimes increasingly include extraterritorial elements, requiring enhanced interaction between States, it is becoming more pressing to coordinate respect for these principles. States must uphold them while also respecting their own national principles of criminal law and any specific principles outlined in the instruments of the regional bodies to which they are party.