(This version of the November 22nd story corrects deadline for parties to register candidates in eleventh par)

Mexico presidential candidate Andres Manuel Lopez Obrador of the National Regeneration Movement (MORENA), gives a speech as he presents his manifesto in Mexico City, Mexico, November 20, 2017. REUTERS/Henry Romero

MEXICO CITY (Reuters) - Mexican leftist presidential hopeful Andres Manuel Lopez Obrador showed leads over potential rivals in two newspaper polls published Wednesday, shortly after he unveiled key policies of his campaign platform ahead of next July’s election.

Lopez Obrador is almost certain to be the candidate for his National Regeneration Movement (MORENA), but other parties have yet to announce who will run for them, making accurate polling difficult.

The survey in business newspaper El Financiero showed Lopez Obrador, a former Mexico City mayor who has already vied twice for the presidency, ahead in any of ten potential candidate groupings with leads ranging from 5 to 15 percentage points.

A separate poll in national daily El Universal showed AMLO, as the politician is known locally, at the top in six candidate combinations but with smaller margins, ranging from 5 to 10 points.

The 64-year-old laid out his 2018 policy platform on Monday, vowing to boost infrastructure spending without upsetting economic stability. He also published a 415-page manifesto outlining goals such as cleaning up graft with tighter financial regulations.

Lopez Obrador narrowly lost in 2006 and by a larger margin in 2012, in both cases refusing to accept results he dismissed as marred by fraud.

He previously ran a popular, moderate government as mayor of Mexico City, but rivals depict him as a dangerous firebrand and liken his policies and style to the socialist project in crisis-hit Venezuela.

Next year’s election is expected to be contested by multiple candidates including independents for the first time, which will fragment the vote, a change that could favor either Lopez Obrador or the ruling Institutional Revolutionary Party (PRI).

President Enrique Pena Nieto is barred by law from a second term.

In both polls, Interior Minister Miguel Angel Osorio Chong emerges as the strongest potential candidate for the ruling party, which is considering at least four high-ranking officials.

Mexican political parties have until March to formally register candidates, but most have set a mid-December deadline to benefit from a longer campaign period.

A coalition headed by the center-right National Action Party (PAN) and center-left Party of the Democratic Revolution (PRD) is also contemplating several options for candidacy.

El Universal conducted 1,000 face-to-face interviews between Nov. 10 and 17 nationwide, resulting in a 3.53 percent margin of error. El Financiero conducted 1,004 face-to-face interviews between Nov. 11 and 16 nationwide, and said the poll has a 3.1 percent margin of error.