NEW YORK (Reuters) - AT&T Inc is planning to announce on Wednesday that it will expand its Latin American reach for business customers through a collaboration with Mexican billionaire Carlos Slim's America Movil.

AT&T will be able to do business in 15 countries, including Argentina, Chile and Colombia, through connections with America Movil networks, according to a representative for AT&T.

Terms of the agreement were not disclosed. The deal will also extend AT&T's reach to Costa Rica, Dominican Republic, Ecuador, El Salvador, Guatemala, Honduras, Nicaragua, Paraguay, Peru and Uruguay.

Previously, AT&T's Latin American focus was primarily on Mexico and Brazil.

AT&T has a long-standing relationship with America Movil and the U.S. company holds a roughly 9 percent stake in the company and has executives on its board of directors.

Since AT&T has been exploring possibilities for expanding in Europe and America Movil has a presence there, some analysts have speculated the companies could combine forces in Europe.

(Reporting by Sinead Carew; Editing by Nick Zieminski)