UPDATE 1-America Movil sees approval of partial Telmex separation by year-end

(Adds details on Telmex separation)

MEXICO CITY, July 19 (Reuters) - America Movil, Latin America's largest telecommunications company by number of subscribers, expects approval from Mexico's telecoms regulator to separate part of its Telmex unit in the fourth quarter of this year or the first three months of 2018, its chief executive said on Wednesday.

Mexico's Federal Telecommunications Institute (IFT) said in March that America Movil, controlled by the family of Mexican billionaire Carlos Slim, must separate part of its network infrastructure into a new entity.

The move ratcheted up antitrust measures against America Movil, which has long been dominant in Mexico.

Talks between America Movil and regulators on the details of the separation are ongoing, Chief Executive Daniel Hajj told analysts on a conference call to discuss the company's second-quarter results.

But Hajj said the discussions have not touched on whether America Movil will be granted a license to offer pay television in Mexico, something the company has long sought. (Reporting by Julia Love; Editing by Matthew Lewis)