Abstract
In his fight against terrorism, the action of Security Council has witnessed an enormous progress. This progress was seen on both normative and institutional aspects leading towards a diversification of the counter terrorism mechanisms. The necessity of its definition seems be bypassed on the benefit of its eradication and suppression especially because of its gradual mutation and the highly powers given to its perpetrators. The United Nations Security Council concentrates its effort, in the mechanisms of counter terrorism, by increasing its normative powers towards a legislative one by gaining considerable prerogatives. On the institutional aspect, the Security Council has monopolized the maintain of international peace and security task, by giving the General Assembly a residual and facultative role. This power regaining is reflected on his ability to create subsidiary organs, especially after the 11th of September 2001. The amplification of the counter terrorism mechanisms was materialized by the submergence of old and fundamental aspects in international public law such as the concept of self-defense. A concept that will jeopardize the collective security system when States will unilaterally will use military force in their counter terrorism quest.