Jose "Pepe" Figueres Ferrer (1906-90), a moderate socialist, was elected president of Costa Rica in 1953. Dictatorial president Anastasio Somoza (1896-1956) of Nicaragua claimed that members of the Caribbean Legion, a group of political exiles from Caribbean nations, participated in a plot to assassinate him with Figueres's help (the legion had backed Figueres in his election); Somoza apparently made plans to retaliate and supported Rafael Calderon Guardia (1900-70), a disgruntled former president of Costa Rica, who led a band of rebels south from Nicaragua and seized the northern Costa Rican border town of villa Quesada on the Pan American Highway (January 11, 1955). Figueres immediately appealed to the Organization of American States to investigate; its commission discovered that the rebels' supplies and war material were coming from Nicaragua. As soon as this was publicly announced, Nicaragua ceased supporting the rebels, who were mostly Costa Ricans. Meanwhile, the United States had sold four fighter planes to Costa Rica. Some heavy fighting occurred in several towns, but the rebels were no match for the popularly backed government forces and were driven north over the border into Nicaragua. In early 1956, Costa Rica and Nicaragua agreed to cooperate in a surveillance of their border.