The America Movil logo is seen on the wall of the reception area in the company's corporate offices in Mexico City August 12, 2015. REUTERS/Henry Romero

MEXICO CITY (Reuters) - Mexico's telecoms regulator said on Thursday that billionaire Carlos Slim's America Movil AMXL.MX has 65 working days to present a proposal for the legal separation of a part of its fixed-line unit Telmex.

The Federal Telecommunications Institute (IFT) has stepped up antitrust rules against the company, ordering it to create an independent entity from fixed-line unit Telmex to offer competitors access to infrastructure.