Mexico investigates 3 officials from state oil company Mexico President Andres Manuel Lopez Obrador says three management-level officials at Mexico's state-controlled petroleum company will be asked to resign as investigations proceed into suspicious contracts awarded to universities for technical expertise

MEXICO CITY -- Mexico President Andres Manuel Lopez Obrador said Thursday that three management-level officials at Mexico's state-controlled petroleum company will be asked to resign as investigations proceed into suspicious contracts awarded to universities for technical expertise.

"We can't tolerate anything that has to do with corruption or even accept suspicions," he said.

Mexico comptroller Irma Erendira Sandoval said that the Pemex officials, including the current head of exploration and production, had signed off on 25 suspicious contracts since 2012.

The contracts for technical assistance were subcontracted various times, despite language barring the practice, Sandoval said. The result was higher costs to the company for services that did not meet its needs.

The three Pemex officials, as well as people close to them, were also found to be partners in some of the subcontracted firms. Other firms appeared to be empty fronts, she said. Investigators have dubbed the fraud a "master scam."

The investigations continue and findings will be turned over to federal prosecutors, Sandoval said. Previous audits at Pemex had raised flags about the contracts, but Sandoval said her predecessor in the administration of former President Enrique Pena Nieto had cleared them and not followed up.

The government is also analyzing the employees' property.

Lopez Obrador has made rooting out government corruption his administration's priority and speaks regularly about cleaning up Pemex, once the pride of Mexico but now a company that suffers from falling production and massive debt.