MEXICO CITY (Reuters) - The leftist party of presidential hopeful Andres Manuel Lopez Obrador was in a photo-finish race to strip control of Mexico's most populous state from the country's ruling party, polls showed on Wednesday.
A victory in Sunday's election in the State of Mexico would hand Lopez Obrador's three-year-old party its first state government, showing its anti-corruption message has mass appeal and adding momentum to his run for the presidency in 2018.
President Enrique Pena Nieto's Institutional Revolutionary Party (PRI) has governed the State of Mexico, which rings Mexico City, for nearly nine decades.
Financial markets are closely watching the progress of Lopez Obrador, a divisive figure with nationalist leanings.
If Lopez Obrador does win in 2018, it could stoke tensions with the United States after President Donald Trump's electoral campaign broadsides against Mexico, such as calling on that country to pay for a wall on the U.S. border.
A poll in the national newspaper Reforma showed Delfina Gomez of his National Regeneration Movement (MORENA) party had 31.9 percent support to be governor of the state of 16 million people where one in eight of the nation's voters live.
The PRI candidate, Alfredo del Mazo, was behind with 30.7 percent. But the gap between the two was within the survey's 3.2 percent margin of error.
A second poll in newspaper El Universal showed del Mazo ahead with 33.8 percent of support and Gomez with 29.3 percent.
However, both surveys showed a strong antipathy towards the PRI. The Reforma poll showed 75 percent of voters wanted another party to govern the state, with 66.2 percent of those surveyed by El Universal expressing the same view.
Less than one-fifth of voters in either poll expressed a desire for the PRI to remain in government.
Del Mazo is battling against a widely held view that his party is corrupt and has failed to rein in crime.
Wednesday is the last day of campaigning for the election. Votes will also be held on Sunday in the states of Coahuila and Nayarit, both also governed by the PRI.
Pena Nieto is a former governor of the State of Mexico.
The PRI portrays Lopez Obrador in the mold of Venezuela's left-wing leaders, but the veteran campaigner has moderated some economic policies in latest bid for the presidency and no longer vows to overturn an energy reform ushered in by Pena Nieto.
The Reforma poll was conducted through 1,200 interviews at home between May 24 and May 29. El Universal's poll held 1,000 face-to-face interviews between May 26 and May 29 and has a 3.1 percent margin of error.
Reporting by Frank Jack Daniel; Editing by Mark Trevelyan and W Simon