New NAFTA talks aim to clear pathway to toughest issues

(Adds comment from Mexican official saying no counterproposal on rules of origin has been presented yet)

By Anthony Esposito and Sharay Angulo

MEXICO CITY, Feb 25 (Reuters) - Mexico and Canada aim to finish reworking less contentious chapters of the NAFTA trade deal with the United States in new talks that began on Sunday, hoping to clear the path for a breakthrough on the toughest issues before upcoming elections.

In six months, negotiators have made progress on the technical details of a revamped North American Free Trade Agreement, but made little advance on strong demands for change made by the administration of U.S. President Donald Trump.

Ranging from calls for major changes to automotive content rules and dispute resolution mechanisms, to imposing a clause that could automatically kill NAFTA after five years, the chief stumbling blocks laid by the White House look unlikely to be removed in the latest Mexico City round, officials said.

Trump frequently threatens to walk away from NAFTA unless big changes are made to a pact he blames for U.S. manufacturing job losses.

"I think there's going to be major progress on the technical issues and major obstacles on the critical issues," Bosco de la Vega, head of the Mexico's National Agricultural Council farm lobby, said of the talks running until March 5.

Once agreement is reached on technical chapters such as state-owned enterprises, barriers to trade and e-commerce, about 10 percent of the modernized accord would eventually be left over for political leaders to work out, de la Vega estimated.

A schedule for the latest round showed that the discussions for the first three days would include rules of origin, an issue at the heart of the Trump administration's demand to raise the amount of auto content sourced from the NAFTA region.

Under NAFTA, at least 62.5 percent of the net cost of a passenger car or light truck must originate in the region to avoid tariffs. Trump wants the threshold raised to 85 percent.

"You can't have a successful negotiation if there's no change to the rules of origin," said a Mexican official, speaking on condition of anonymity, adding: "It won't be 85 percent. We're not sure what the number is going to be."

Mexican Economy Minister Ildefonso Guajardo has said his negotiating team aims to present a proposal on rules of origin, although he has not provided details.

On Sunday evening, the Mexican official told Reuters: "We don't have a counterproposal yet."

Any final agreement would need to be reached between Trump and auto-sector leaders in the United States who oversee the NAFTA region, an industry source close to the process said.