The invasion of Puerto Rico by the American military forces was known as the Puerto Rican Campaign. On May 10, 1898, Spanish forces, under the command of Captain Ángel Rivero Méndez in the fortress of San Cristóbal in San Juan, exchanged fire with the , and on May 12 a fleet of 12 American ships bombarded San Juan. On June 25, the arrived in San Juan and blockaded the port. Captains Ramón Acha Caamaño and José Antonio Iriarte, both natives of Puerto Rico, were among those who defended the city form Fort San Felipe del Morro. They had three batteries under their command, which were armed with at least three 15 cm Ordóñez cannons. The battle lasted three hours and resulted in the death of Justo Esquivies, the first Puerto Rican soldier to die in the Puerto Rican Campaign.