MEXICO CITY (AP) — The Mexican government on Wednesday unveiled its proposed rules for a historic opening of the state-owned oil and energy industry, saying contracts and production licenses should be put out for public bid and go to the company that offers the best return.

Energy Secretary Pedro Joaquin Coldwell said the service station monopoly of state-owned Petroleos Mexicanos would fade only gradually as the necessary distribution and other infrastructure is made ready. Private companies will not be allowed to immediately open gas stations to compete with it.