By Alizeh Kohari and Lizbeth Diaz

MEXICO CITY (Reuters) - A former energy official continued his rapid rise in Mexico's political establishment to become leader of the ruling party on Tuesday, vowing to rid it of corruption after scandals that have battered the authority of President Enrique Pena Nieto.

Enrique Ochoa, head of the Federal Electricity Commission (CFE) until he resigned on Friday, was confirmed as chairman of the Institutional Revolutionary Party (PRI) by an internal committee, and immediately said the party must clean up its image.

"It's unacceptable to turn a blind eye, we must react," Ochoa told a crowd of party members. "We must be a party that flags corruption in our own governments, one that demands that they are held accountable and even subject to dismissal."

Pena Nieto's office accused two state governments on Monday of flouting anti-corruption laws, a move that political analysts saw as a warning to their outgoing PRI governors, who have been tarnished by graft accusations.

The PRI has ruled Mexico continuously since 1929, barring a hiatus from 2000 to 2012, and its name has become synonymous with political corruption over time.

Pena Nieto's administration has done little to change that perception. He, his wife, and his finance minister were all embroiled in a damaging conflict-of-interest scandal when it emerged they bought homes from government contractors.

A subsequent probe led by an official close to Pena Nieto found no evidence of wrongdoing.

Ochoa, a combative and ambitious lawyer who cut his teeth in a string of technocratic roles, had seen little of the limelight but has now been thrust into the very public role of leading the PRI into the 2018 presidential elections.

He replaces Manlio Fabio Beltrones, who stepped down after voters angry about graft and gang violence punished the PRI in regional elections. Such anger was epitomized by the apparent massacre in 2014 of 43 students by a drug gang working with corrupt police.

A close ally of Pena Nieto, Ochoa was instrumental in crafting the president's landmark 2013 energy reform while deputy energy minister. He took over at the CFE in 2014, where he presided over a reduction in costly industrial power rates.

Some senior PRI figures in the government would like to see Ochoa run for president in 2018, although Interior Minister Miguel Angel Osorio Chong is better known.

Ochoa, 43, also holds a doctorate in political science from Columbia University.

(Writing by Alexandra Alper; Editing by Dave Graham, Chris Reese and Paul Tait)