MEXICO CITY (Reuters) - Mexico’s leftist National Regeneration Movement (MORENA) party chief Andres Manuel Lopez Obrador ruled out on Sunday aligning with other traditional political parties in the run-up to the 2018 presidential elections.

“Those who associate themselves and deal with the mafia of power are nothing more than opportunist mercenaries and politicians ... as such we can’t move forward with those parties,” Lopez Obrador said in a speech to MORENA party members and supporters in Mexico City.

He said he was referring to Mexico’s biggest political parties, including President Enrique Pena Nieto’s Institutional Revolutionary Party (PRI), the center-right National Action Party (PAN), and the country’s main leftist party, the Party of the Democratic Revolution (PRD).

MORENA party members will have to ratify Lopez Obrador’s recommendation.

Lopez Obrador, a divisive figure with nationalist leanings who has led a number of early polls for the 2018 presidential vote, added that he would not align MORENA with the smaller Green, Citizens Movement, New Alliance and Encuentro Social parties.

He has asked party members to support MORENA forging an alliance with Mexico’s small Labor Party.

Known as AMLO, the silver-haired politician, has twice been a runner-up for Mexico’s presidency.