MEXICO CITY (Reuters) - Mexico’s left-wing presidential front-runner Andres Manuel Lopez Obrador, who is trying to calm a fierce exchange with some of the country’s business leaders, said on Monday he could offer a concession for Mexico City’s new airport.

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Lopez Obrador, ahead by double digits in all major polls, has threatened to cancel the new $13 billion airport, arguing it is full of corruption and too expensive.

His position on the airport and commitment to review contracts signed with oil majors under an energy reform in recent years, along with high-profile sparring with some Mexican tycoons, worry some investors.

But he said at a tourism event on Monday that the airport, Mexico’s biggest infrastructure project, could be put out to the private sector in a concession, like most other airports in the country.

“Why don’t we do a concession? I wouldn’t have a problem,” said the candidate, who wants to stimulate the economy with an infrastructure push. “I’m not going to put half of public investment into one project,” he added.

The same idea was recently raised publicly by Mexico’s richest man, Carlos Slim, who said he did not understand why the project was not privately financed in a concession.

Lopez Obrador’s softer language and the prospect of a concession reflect the tone of his comments at a campaign rally on Sunday, where he tried to take the heat out of an exchange with a group of businessmen he has accused of corruption.

“Look, purely by coincidence I have a white handkerchief,” he said in the northern state of Nuevo Leon, waving it as a symbol of the “peace and love” he said he wanted with business. He said his argument was with a small group that had benefited from close ties to government, not businesses in general.

Last week, Lopez Obrador named several members of Mexico’s elite he said were “influence traffickers” that benefit from corruption, provoking outrage and a full-page newspaper ad from a powerful business coalition, condemning what they described as personal attacks and slander.

A separate business body, CCE, on Monday published a letter assuring that they were part of the solution, not the problem.