The leaders agreed to hold a presidential summit in Buenos Aires, Argentina, later this month to discuss the matter after Venezuelan President Hugo Chavez raised it during a ceremony to inaugurate Ecuadorean President Rafael Correa as temporary president of the Union of South American Nations, or Unasur. Luiz Inacio Lula da Silva, of Brazil, Cristina Fernandez, of Argentina, Evo Morales, of Bolivia, Fernando Lugo, of Paraguay, and Ecuador's Correa also expressed unease with the plan. ''I don't want to sabotage your ceremony Rafael ... (but) we are very worried,'' said Chavez, who added that he believes the bases will destabilize the region. ''This could provoke a war in South America,'' Chavez said. During his weekly television and radio address Sunday the Venezuelan president told his military to be ''ready for combat'' in case of a Colombian provocation. Read more here. Semana International delivers news about Colombia in English. Find more in our home.