MEXICO CITY, March 13 (Xinhua) -- Mexico on Tuesday denied there was any connection between the proposed U.S. border wall and ongoing negotiations with Washington to update the 1994 North American Free Trade Agreement (NAFTA).

"There is, was and will be categorically no relationship between the negotiation of the free trade agreement and the wall, under any circumstances," Economy Minister Ildefonso Guajardo told reporters at a press conference.

Guajardo, who heads Mexico's negotiating team, made the remarks during U.S. President Donald Trump's first inspection of eight prototypes of the wall on display in San Diego, California, a town that shares a border with Tijuana, Mexico.

The alleged link between the wall and possible new NAFTA terms, according to Guajardo, stems from a January Wall Street Journal interview with Trump, in which the president suggested Mexico could pay for the border wall through changes made to the trade pact.

But "no matter how you look at it, there is no relationship between NAFTA and any discussion of the wall," said Guajardo.

The three NAFTA partners, namely the United States, Canada and Mexico, have closed some chapters of the agreement, but disagree on several key issues, including rules of origin in the automotive sector, which stipulate what percentage of a vehicle should be regionally manufactured to be exempt from import duties.

The United States proposed changing the existing rules so that a minimum of 85 percent of an automobile must be made in North America, with at least 50 percent of parts made in the United States.

Mexico and Canada have in the past said they want both rates to remain at 62.5 percent, but on Tuesday Guajardo signaled Mexico was willing to budge.

"Aiming to leave unchanged a rule of origin that was devised 26 years ago lacks any argumentative strength. That the rule of origin is going to change is a fact," said Guajardo, without offering specifics.