MEXICO CITY — Mexican state oil monopoly Pemex plans to form a new company to explore for and exploit shale gas and deep-water crude in the United States as it seeks to branch out beyond its borders, the company's CEO said in a newspaper interview.

The company should be set up by the end of the year, Emilio Lozoya told the Wall Street Journal in an interview published on Monday. Pemex is struggling to stem a near decade-long slide in output.

The move comes as President Enrique Pena Nieto seeks to push through a proposed energy sector overhaul in which Mexico will open up a range of new and mature oil and gas fields in Mexico and its waters to private firms.

"Pemex will be starting a new company that will work on the shale-gas and shale-oil fields in the U.S. and in the deep-water side of the U.S.," Lozoya told the paper. "We are already exploring numerous projects."

Pemex already has a stake in the Deer Park refinery in Texas via a joint venture with Royal Dutch Shell Plc.

Currently under its constitution, Mexico can give private oil companies neither concessions nor profit-sharing contracts to exploit either shale gas or deep water crude at home.