August, Pereira Pinto sighted the Villa del Salto, which was conveying troops to fight the Colorados. The Villa del Salto ignored warning shots and a demand to surrender; after a desperate run from the Brazilian warships, it escaped to Argentine waters. This first skirmish of the war prompted the Uruguayan government to sever all diplomatic ties with Brazil on 30 August. On 7 September, Pereira Pinto again encountered the Villa del Salto sailing from Salto to Paysandú. The two Brazilian corvettes attacked the Uruguayan ship as it again tried to escape to Argentina. The battle ended when the Villa del Salto ran aground near Paysandú, where its crew set it on fire to prevent it falling into Brazilian hands. Meanwhile, the General Artigas had been sold to prevent its capture by the Brazilians. To Flores, Brazil's military operations against the Blanco government represented a priceless opportunity, since he had been unable to achieve any lasting results during the rebellion. He entered talks with Saraiva, winning the Brazilian government over, after promising to settle their claims refused by the Blanco government. The Brazilian plenipotentiary minister gave instructions to Tamandaré to form a joint offensive with the Colorado leader and overthrow the Blancos. On 20 October, after a swift exchange of letters, Flores and the Brazilian vice-admiral formed a secret alliance. Colorado–Brazil joint offensive Sieges of Uruguayan towns The Brazilian naval fleet in Uruguay was supposed to work in conjunction with a Brazilian land force. But months passed, and the "Army of the South" (called the "Division of Observation" until the ultimatum) stationed in Piraí Grande (in Rio Grande do Sul) was still not ready to cross into Uruguayan territory. Its main objectives were to occupy the Uruguayan towns of Paysandú, Salto and Melo; once taken, they were to be handed over to Flores and his Colorados. On 12 October, a brigade led by Brigadier José Luís Mena Barreto detached from the main army. Two days later, near the Brazilian town of Jaguarão, the force invaded Uruguay's Cerro Largo Department. After skirmishes failed to halt their march, the Blancos abandoned Melo, and the brigade entered this capital of Cerro Largo unopposed, on 16 October. After handing over control of Melo to the Uruguayan Colorados, the Brazilians withdrew on 24 October, to rejoin their Army of the South. The next Brazilian target was Salto. Pereira Pinto sent two gunboats under First Lieutenant Joaquim