Article V of the WEU Treaty and Article 5 of the North Atlantic Treaty

Modified Brussels Treaty

Treaty of Economic, Social and Cultural Collaboration and Collective Self-Defence Signed at Brussels on March 17, 1948, as Amended by the "Protocol Modifying and Completing the Brussels Treaty"

Signed at Paris on October 23, 1954 



If any of the High Contracting Parties should be the object of an armed attack in Europe, the other High Contracting Parties will, in accordance with the provisions of Article 51 of the Charter of the United Nations, afford the Party so attacked all the military and other aid and assistance in their power.

The North Atlantic Treaty

Washington D.C. - 4 April 1949


Article 5

The Parties agree that an armed attack against one or more of them in Europe or North America shall be considered an attack against them all and consequently they agree that, if such an armed attack occurs, each of them, in exercise of the right of individual or collective self-defence recognised by Article 51 of the Charter of the United Nations, will assist the Party or Parties so attacked by taking forthwith, individually and in concert with the other Parties, such action as it deems necessary, including the use of armed force, to restore and maintain the security of the North Atlantic area. 

Any such armed attack and all measures taken as a result thereof shall immediately be reported to the Security Council. Such measures shall be terminated when the Security Council has taken the measures necessary to restore and maintain international peace and security (1).