Action of 13 June 1898 decided to withdraw. At the outbreak of the Spanish–American War Cienfuegos was a strategically important port due to its facilities and good communications with Havana. Some prewar plans recommended its prompt capture, but instead it was blockaded, along with some other important ports of the southern coast of Cuba such as Santiago de Cuba and Manzanillo. The most powerful Spanish naval units of the island, meanwhile, had been gathered in Santiago, and submarine defenses consisting mainly of torpedoes had been installed in the major ports of Havana, Cienfuegos, Santiago and San Juan de Puerto Rico. The naval units based in
Battle of Santiago de Cuba sued for peace. Spain surrendered in August and the war was over. Some of the terms of surrender were as follows: These terms, upon which both sides came to an agreement during the 1898 Treaty of Paris (1898) negotiations, decided the fate of the remaining Spanish troops, vessels, and the matter of Cuba's sovereignty. Spanish prisoners of war that were not wounded were sent to Seavey's Island at the Portsmouth Naval Shipyard in Kittery Maine, where they were confined at Camp Long from July to September 1898. The Americans treated Spain's officers, soldiers, and sailors with great respect. Ultimately, Spanish