Union of South American Nations in Mitad del Mundo, Ecuador, where the cornerstone was laid for the headquarters of the General Secretariat of the Union. In April 2018, six countries suspended membership: Argentina, Brazil, Chile, Colombia, Paraguay and Peru. In August 2018, Colombia announced its withdrawal from the organization. At the Third South American Summit on 8 December 2004, presidents or representatives from 12 South American nations signed the "Cusco Declaration", a two-page statement of intent announcing the foundation of the South American Community. Panama and Mexico attended the signing ceremony as observers in Brazil. The mechanics of the new entity came out of the
Union of South American Nations Union of South American Nations The Union of South American Nations (USAN; , UNASUR; , UNASUL; , UZAN; and sometimes referred to as the South American Union) is an intergovernmental regional organization comprising twelve South American countries. The UNASUR Constitutive Treaty was signed on 23 May 2008, at the Third Summit of Heads of State, held in Brasília, Brazil. According to the Constitutive Treaty, the Union's headquarters will be located in Quito, Ecuador. On 1 December 2010, Uruguay became the ninth state to ratify the UNASUR treaty, thus giving the union full legality. As the Constitutive Treaty entered into force