Updated

A majority of Mexico's state legislatures have now approved sweeping energy reform legislation that will allow private companies to work in oil and gas exploration and production.

In all, 17 of the country's 31 state legislatures have approved the reform of the state-controlled oil industry that Congress passed last week.

The states' approval was needed because the legislation changes the country's Constitution, which previously banned such private contracts.

San Luis Potosi state's legislature became the 17th to approve the bill on Monday.

The federal Congress must still certify the states' ratification, and the president must sign it into law.

The state-run Petroleos Mexicanos oil company has lacked the investment money and expertise to reverse a decade of falling production.