Presidents from most South American countries have gathered in Brazil for a meeting of the Mercosur trading group.
The two-day meeting in Rio de Janeiro began Thursday.
One of the main issues under discussion is how to make Mercosur more responsive to the social concerns of the member countries.
The push for a change of direction for the five-member alliance is coming from Venezuela's leftist President Hugo Chavez. Ecuador and Bolivia, both also led by leftist governments, are seeking to join the group.
Officials say the trade bloc now accounts for one trillion dollars in annual economic activity and includes 250 million people.
Argentina, Brazil, Paraguay and Uruguay formed Mercosur in 1991. Venezuela joined in July of last year. Chile and Bolivia are associate members.
Some information for this report was provided by AP and Reuters.