MEXICO CITY — Mexico's presidential hopefuls are rushing to deny rumors of possible late-campaign alliances or candidate switches in a race that has been dominated by leftist Andres Manuel Lopez Obrador.

Much of Mexico's elite wants to stop Lopez Obrador from winning the July 1 election, fearing he would undo market-oriented economic reforms.

A poll published Wednesday by the newspaper Reforma gave Lopez Obrador an 18 percentage point lead over Ricardo Anaya, who heads a left-right opposition coalition. The survey had margin of error of four percentage points.

Lopez Obrador claimed Tuesday that business leaders tried to persuade the governing Institutional Revolutionary Party to switch its support to Anaya from its lagging third-place candidate, Jose Antonio Meade.

Anaya himself has called on those frightened by Lopez Obrador to unite behind him.

"I am completely open to building with whoever I must build with to win this election and give a viable future to this country," he said recently when asked about whether he would meet with President Enrique Pena Nieto to look for an alliance with the governing Institutional Revolutionary Party, or PRI.

Anaya later denied that he would reach an accord with the PRI hierarchy but said he was willing to extend his hand to the party's supporters in a campaign that he characterized as being between him and Lopez Obrador.

Government spokesman Eduardo Sanchez on Wednesday denied there was any such alliance effort underway, labelling it "fake news."

Also on Wednesday, indigenous independent hopeful Maria de Jesus Patricio said she wouldn't campaign for Lopez Obrador.

Patricio, who tried but failed to gather enough petition signatures to get on the ballot, said she "will not accept any alliance with any candidate or party" in the elections.

"We don't fit in their game," said Patricio, who is better known by her nickname, "Marichuy."

She said she wouldn't call on supporters to stay away from the polls, but also wouldn't encourage them to vote.