Mexico's federal anti-corruption agency says it will investigate whether federal officials were involved in payments allegedly made by U.S. retailer Wal-Mart to speed up permits for building stores in Mexico.
The Public Administration Department says it will look at whether any federal permits were granted and take appropriate action if irregularities are found.
The department had previously suggested the allegations in a New York Times report were a matter for local governments.
In Mexico, zoning, land use and construction permits are usually handled by municipal governments unless an environmental impact statement is needed in sensitive or protected areas.
The department said Wednesday it will ask U.S. officials for any information they have, and pass it on to local governments.