Saraiva had presented an ultimatum to the…

Saraiva had presented an ultimatum to the Uruguayan government on August 4, stating that there will be a formal declaration of war if it does not accede.

The Uruguayan government has refused to accept the ultimatum, and on August 10, Saraiva had informed Aguirre that the Brazilian commanders will receive orders to begin retaliation.

The following day, Saraiva had delivered to the Vice Admiral Joaquim Marques Lisboa (the Baron of Tamandaré and commander of the Brazilian naval forces in Uruguay) the orders to initiate war operations.

Tamandaré has under his command twelve steamships: the frigate Amazonas; corvettes Niterói, Belmonte, Beberibe, Parnaíba, Jequitinhonha and Recife; and gunboats Mearim, Araguaia, Ivaí, Itajaí and Maracanã.

The Brazilian admiral creates a naval division to patrol the Uruguay River under the command of Francisco Pereira Pinto (later Baron of Ivinhema) that consists of the ships Jequitinhonha, Araguaia and Belmonte.

On August 25, the officer Pereira Pinto sights the Uruguayan steamship Vila del Salto and, despite the warning shots to surrender, it manages to escape to Argentina after a desperate flight from the Brazilian warships.

The first battle of the war will result n the breaking off of diplomatic relations by the Uruguayan government on August 30.