Reuters cited Mexico's Economy Minister Mr Ildefonso Guajardo as saying that the country had to be realistic about the rules of origin for automobiles under the North American Free Trade Agreement (NAFTA), saying that the current level will change.

Under NAFTA, at least 62.5 percent of the net cost of a passenger car or light truck must originate in the United States, Canada or Mexico to avoid tariffs. US President Donald Trump's administration wants to hike this to 85 percent.

Mr Guajardo said on local television that "You have to be very prudent on what the level is because you can shoot yourself in the foot. Let's put a realistic integration figure that everyone agrees on, its not going to be the current 62.5 percent but it also can't be 85."