<P> The Puerto Rican Campaign was an American military sea and land operation on the island of Puerto Rico during the Spanish--American War . The offensive began on May 12, 1898, when the United States Navy attacked the capital, San Juan . Though the damage inflicted on the city was minimal, the Americans were able to establish a blockade in the city's harbor, San Juan Bay . On June 22, the cruiser Isabel II and the destroyer Terror delivered a Spanish counterattack, but were unable to break the blockade and the Terror was damaged . </P> <P> The land offensive began on July 25, when 1,300 infantry soldiers led by Major General Nelson A. Miles disembarked off the coast of Guánica . After controlling the first skirmish, the Americans advanced to Coamo, where they engaged Puerto Rican and Spanish troops in battle . The battle concluded when the allied soldiers retreated after the battle left two dead on their side, and four on the American side . The United States was able to seize control of Fajardo on August 1, but was forced to withdraw on August 5 after a group of 200 Puerto Rican--Spanish soldiers led by Pedro del Pino gained control of the city, while most civilian inhabitants fled to a nearby lighthouse . The Americans encountered larger opposition as they advanced towards the main island's interior . They engaged in two crossfires in Guamani River and Coamo, both of which were inconclusive as the allied soldiers retreated . A battle in San Germán concluded in a similar fashion with the Spanish retreating to Lares . </P> <P> On August 9, 1898, American troops that were pursuing units retreating from Coamo encountered heavy resistance in Aibonito and retreated after six of their soldiers were injured . They returned three days later, reinforced with artillery units and attempted a surprise attack . In the subsequent crossfire, confused soldiers reported seeing Spanish reinforcements nearby and five American officers were gravely injured, which prompted a retreat order . All military actions in Puerto Rico were suspended on August 13, after U.S. President William McKinley and French Ambassador Jules Cambon, acting on behalf of the Spanish government, signed an armistice whereby Spain relinquished its sovereignty over the territories of Puerto Rico, Cuba, the Philippines and Guam . </P> <P> In 1890, Captain Alfred Thayer Mahan, a member of the Navy War Board and leading U.S. strategic thinker, wrote a book titled The Influence of Sea Power upon History in which he argued for the creation of a large and powerful navy modeled after the British Royal Navy . Part of his strategy called for the acquisition of colonies in the Caribbean Sea which would serve as coaling and naval stations, and serve as strategical points of defense upon the construction of an Isthmusian canal . </P>

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