A/57/173 article 3 is thus wider than that provided by articles 32 and 33 of the United Nations 1951 Convention on the Status of Refugees. 30 33. With respect to extradition, attention is drawn to the conclusions of the UNHCR Executive Committee (No. 17 [XXXI]-1980) on Problems of Extradition affecting Refugees, which called upon States to ensure that the principle of non-refoulement is duly taken into account in treaties relating to extradition and as appropriate in national legislation on the subject, and stressed that nothing in those conclusions should be considered as affecting the necessity for States to ensure, on the basis of national legislation and international instruments, punishment for serious offences, such as the unlawful seizure of aircraft, the taking of hostages and murder. In line with that recommendation, the Special Rapporteur would like to encourage States to include the principle aut dedere aut judicare in instruments aimed at international cooperation with respect to criminal matters. 34. The Special Rapporteur would like to remind States that in respect of certain crimes such as crimes against humanity and presumably certain terrorist acts, international law permits, and in some cases requires, States to exercise jurisdiction on the mere basis of presence in their territory of suspected perpetrators of such crimes. In a number of countries national legislation to that effect may still need to be enacted. He also would like to stress the possibility of prosecution of those charged with terrorist acts that qualify as crimes against humanity under the Rome Statute of the International Criminal Court, with due regard to the principle of complementarity laid down in the Rome Statute. 35. Finally, the Special Rapporteur would like to appeal to all States to ensure that in all appropriate circumstances the persons they intend to extradite, under terrorist or other charges, will not be surrendered unless the Government of the receiving country has provided an unequivocal guarantee to the extraditing authorities that the persons concerned will not be subjected to torture or any other forms of ill-treatment upon return, and that a system to monitor the treatment of the persons in question has been put into place with a view to ensuring that they are treated with full respect for their human dignity. II. International and national mechanisms for visits to places of deprivation of liberty 36. In his last report to the General Assembly, the previous Special Rapporteur addressed the general issue of prevention and transparency31 and advocated replacing the paradigm of opacity surrounding the places of deprivation of liberty by one of transparency. The present mandate-holder fully supports the recommendation made by his predecessor with respect to the importance of external supervision of all places of deprivation of liberty by independent officials, such as judges, prosecutors, ombudsmen and national or human rights commissions, and by civil society as well as by independent monitoring institutions, such as the International Committee of the Red Cross and the European Committee for the Prevention of Torture and Inhuman or Degrading Punishment (CPT) under the European Convention for the Prevention of Torture and Inhuman or Degrading Treatment or Punishment, and the mechanism contemplated by the draft optional protocol to the Convention against Torture and Other Cruel, Inhuman or Degrading Treatment or Punishment. Both the protective and preventive roles of such mechanisms have been duly recognized. 37. The Special Rapporteur welcomes the decision of the fifty-eighth session of the Commission on Human Rights concerning the draft optional protocol, which is the result of a process of consultations and negotiations over the past decade, and whose objective is, as provided for in draft article 1, to establish a system of regular visits undertaken by independent international and national bodies to places where people are deprived of their liberty in order to prevent torture and cruel, inhuman or degrading treatment or punishment. As suggested by the Joint Declaration issued on 26 June 2002 by the Special Rapporteur, the Committee against Torture, the Board of Trustees of the United Nations Voluntary Fund for Victims of Torture and the United Nations High Commissioner for Human Rights on the occasion of the United Nations Day in Support of Victims of Torture (see annex), focused visits by independent multidisciplinary teams of experts to places of detention and other places where persons are deprived of their liberty have proved to be a most effective way to prevent torture. 38. Law enforcement officials and other detention personnel and authorities who are aware that their 11