The conclusion of numerous other treaties have made the following acts international crimes: aircraft hijacking, unlawful acts against the safety of civil aviation, trafficking in women and children, trafficking in narcotic drugs, counterfeiting of currency, kidnapping of diplomats and taking of hostages. The most recent addition to this list of international crimes is international terrorism. The absence of any judicial tribunal to try the perpetrators of these crimes left the matter to the states concerned to prosecute and punish them. As a result, there is no uniformity in the substantive and procedural rules in this regard.