(police, para-military police, army, etc.) and by means of organised private security services(security and surveillance companies, money conveyance outfits, personal protection structures). Internal security generally aims at keeping public order within a country, the full result of which is absolute absence of any form of disorder and insecurity within a State. 1.4. External Security. This expression refers to absence of external agression threat against the State. In the conventional sense of the term, it refers to national defence and usually arises when appropriate measures are taken to protect the country against external threats. The means to ensure external security of the State consist of defence systems and mechanism for obtaining external intelligence information to assess possible threats, determine the initiators and sources thereof; they also include the available forces to take appropriate action or measure to counter such threats. 1.5. National Security. Internal Security and External Security form what is ordinarily known as National Security. In a broader sense, it refers to the security of the State and that of persons living under its jurisdiction. From here, we can foresee the preliminaries of human security to be dealt with later. 1.6. Collective Security. The concept of collective security emerged after the two world wars. Having realized the serious threats to international peace and security, the international community did set up an international security system that is based on peace amongst nations. However, collective security should not be confused with collective defence, although both notions are close. In fact, collective defence involves putting in place a defence system that would cover several States and wherein roles and responsibilities shall be shared. 1.7. Public Security. It aims at ensuring protection of citizens, their properties and activities against violence and troubles by the State. 8