Mexico's antitrust watchdog is fining media giant Televisa almost $4 million for refusing to let a cable operator transmit its channels, the latest in a push to boost competition in the sector.

The Federal Competition Commission decided at a meeting last month to fine Televisa, which controls cable operator Cablevision, but has not yet published details of the ruling, an official at the commission who is not authorized to speak on the record told Reuters on Tuesday.

Televisa, controlled by billionaire Emilio Azcarraga Jean, controls about 70 percent of the broadcast television market share in Mexico, with TV Azteca accounting for most of the rest. That puts any cable company that cannot offer Televisa's programming at a disadvantage.

Televisa, which may appeal the resolution, had no immediate comment. The company has stakes in two other cable companies in Mexico.

($1 = 12.86 pesos)

(Reporting by Noel Randewich)

Mexico