E/CN.4/1989/44 page 50 III. EXISTING GUARANTEES FOR FREEDOM OF THOUGHT, CONSCIENCE, RELIGION AND BELIEF A. At the international level 82. In his earlier reports, the Special Rapporteur mentioned a number of international norms containing provisions concerning the elimination of intolerance and discrimination based on religion or belief (E/CN.4/1987/35, paras. 3-10; E/CN.4/1988/45, para. 54). These norms are found both in international human rights or humanitarian law instruments and in other instruments adopted under the aegis of United Nations specialized agencies such as the International Labour Organisation (ILO) and UNESCO, and concern certain specific aspects of discrimination on grounds of religion or belief. 83. In several cases, the international instruments adopted have provided for monitoring mechanisms so as to ensure the implementation of the provisions by the States parties. Reference may be made in this regard to the activities of the Committee on the Elimination of Racial Discrimination in connection with article 5 of the International Convention on the Elimination of All Forms of Racial Discrimination. Similarly, the Human Rights Committee, set up to ensure the effective implementation of the provisions of the International Covenant on Civil and Political Rights, has studied, particularly in the context of article 18 of the Covenant, the various measures envisaged by States parties to guarantee freedom of religion or belief. 84. As regards the prevention of religious discrimination in the sphere of employment, ILO has also endeavoured to introduce a number of monitoring mechanisms. For example, mention may be made of the most recent observations of the Committee of Experts on the Application of Conventions and Recommendations at its March 1988 session, in particular concerning specific cases of discrimination on the grounds of religion or belief in some countries in the context of the implementation of the provisions of the Abolition of Forced Labour Convention, 1957 (No. 105) and the Discrimination (Employment and Occupation) Convention, 1958 (No. Ill) . Reference may also be made to the latest report of the Committee of Experts on the Application of Conventions and Recommendations submitted to the International Labour Conference at its seventy-fifth session in June 1988. B. At the national level 85. In accordance with article 4 of the 1981 Declaration, States shall make all efforts to ensure a number of guarantees to combat intolerance and discrimination based on religion or belief. As the Special Rapporteur recalled in his initial report (E/CN.4/1987/35, para. 30), the existence, in constitutions or other texts of national legislation, of provisions establishing the principle of freedom of religion and belief does not constitute an absolute guarantee of respect for that principle. Nevertheless, the adoption of such provisions is one of the essential facets of the system guaranteeing the rights and freedoms of religion and belief. This is why, in accordance with the provisions of article 4 (2) of the Declaration, States "shall make all efforts to enact or rescind legislation where necessary to prohibit any such discrimination". In addition to these legislative measures, States are required "to take all appropriate measures to combat intolerance on the grounds of religion or belief in this matter".