Guantanamo Bay Naval Base (also called Gitmo or GTMO) is located on 45 square miles (120 km2) of land and water at Guantánamo Bay, Cuba which the United States leased for use as a coaling (fueling) station following the Cuban-American Treaty of 1903. The base is located on the shore of Guantánamo Bay at the southeastern end of Cuba. It is the oldest overseas U.S. Navy Base, and the only one in a country with which the United States does not have diplomatic relations. The Cuban government opposes the presence of the naval base, claiming that the lease is invalid under international law. The U.S. government claims that the lease is valid.