Israel argued universal jurisdiction based on the "universal character of the crimes in question" and that the crimes committed by Eichmann were not only in violation of Israel law, but were considered "grave offenses against the law of nations itself". It also asserted that the crime of genocide is covered under international customary law. As a supplemental form of jurisdiction, a further argument is made on the basis of protective jurisdiction. Protective jurisdiction is a principle that "provides that states may exercise jurisdiction over aliens who have committed an act abroad which is deemed prejudicial to the security of the particular state concerned".