The United Nations Organisation undertook the gigantic three dimensional task of peace keeping, peace making and peace building in a world which had just been a victim of a devastating world war. Thus, the primary function of the UNO is to maintain international peace and security. This includes collective effective measures for prevention and removal of threats to peace, and suppression of acts of aggression or other breaches of peace. To bring about through peaceful means, adhering to principles of justice and international law adjustment and settlement of international disputes. Thus the cause of action for UNO arises when there is threat to peace, or actual aggression causing breach of peace. The means for settling disputes are recommended to be peaceful but where suppression of aggression is required the Security Council is authorized to use military operations. For instance in Korea, Palestine and Congo and in the Gulf War the UN military forces played a decisive role.