South America's leaders gathered in Brazil's capital on Tuesday as part of an effort by the Brazilian president to revive regional cooperation in energy, crime-fighting and the economy.
The regional bloc previously known as Union of South American Nations, or Unasur, first gathered 15 years ago to boost cooperation between the 12 South American nations. But the group eventually fractured amid the continent's political swings and polarisation, and this is their first meeting for nine years.
Brazilian President Luiz Inacio Lula da Silva suggested at a news conference on Monday that he might consider floating the idea of a regional currency to challenge the US dollar. But he said nothing would be decided during the meeting.
"The main idea is that we need to form a bloc to work together," he said.
The participation of Venezuela's authoritarian President Nicolas Maduro led several countries to withdraw, including Brazil in 2019.
The majority of its current presidents are now leftist or centrist - the Brazilian president met Mr Maduro on Monday, calling the bilateral meeting a "historic moment" for both countries.
Aside from Mr Maduro, another 10 South American presidents are attending the summit, as well as the leader of the Council of Ministers of Peru, where the president, Dina Boluarte, faces charges and cannot leave the country.