Pemex said its chief executive Emilio Lozoya Austin and Lukoil president Vagit Alekperov signed the deal at the World Economic Forum in Davos.

The reform signed by President Enrique Pena Nieto changed the constitution to allow private investment in the country's oil sector for the first time since 1938.

Its goal is to "create conditions to maximise the potential of oil resources in Mexico as well as strengthen Pemex as a productive state enterprise to become more efficient, competitive and transparent," Lozoya Austin said in a statement.

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