[en] The IAEA International Physical protection Advisory Service (IPPAS) provides advice to Member States to assist them in strengthening the effectiveness of their national physical protection system whilst recognizing the ultimate responsibility for physical protection is that of the Member State. The IPPAS is available to all countries with nuclear materials and facilities. The basic concepts, purposes and functions of physical protection are provided in INFCIR/225, 'The Physical Protection of Nuclear Material and Nuclear Facilities' as amended from time to time and 'the Convention on the Physical Protection of Nuclear Material (INFCIR/247/Rev.1). The guidance given in INFCIR/225 recognizes that implementation of these requirements vary from country to country depending on their existing constitutional, legal and administrative systems; the assessment of the threat for the potential theft of nuclear material or sabotage of nuclear facilities; the technical skills and professional and financial resources available to the competent authority; and social customs and cultural traditions. IPPAS missions are performance oriented in that they accept different approaches to the implementation of national physical protection system