“Genocide is the denial of the right to existence of entire human groups, as homicide is the denial of the right to live of individual human beings; such denial of the right of existence shocks the conscience of mankind, results in great losses to humanity in the form of cultural and other contributions represented by these groups, and is contrary to moral law and to the spirit and aims of the United Nations. Many instances of such crimes of genocide have occurred, when racial, religious, political and other groups have been destroyed, entirely or in part. The punishment of the crime of genocide is a matter of international concern