UPDATE 1-Argentine America Movil unit to invest $420 mln

* Investment earmarked for data, broadband and telephone

* Money to be spent next year as part of wider investment (Adds quote, details)

BUENOS AIRES Nov 15 (Reuters) - The Argentine unit of Mexico's America Movil (AMXL.MX)(AMX.N) plans to invest $420 million next year to expand its services, the unit's managing director said on Monday.

Rogelio Viesca Arrache, who heads the firm's Claro unit in the South American country, told reporters the planned investment would be used to expand data, broadband and telephone services.

America Movil, one of the world's biggest telecommunications companies and owned by billionaire Carlos Slim, said in October it planned to invest up to $6 billion in 2011 and that it would focus on the data business.

The company posted surprisingly strong profit margins in the third quarter. [ID:nN28191165] (Reporting by Guido Nejamkis; Writing by Helen Popper) (helen.popper@thomsonreuters.com; +54 11 4318 0655; Reuters Messaging: helen.popper.reuters.com@reuters.net))