Following Mexico's growing rift with the United States over President Donald Trump's plan to build a wall on the border and put a 20 percent import tax on Mexico to pay for it, Mexican billionaire Carlos Slim held a rare news conference in which he offered to assist President Pena Nieto in negotiations.

Slim, who traveled to Florida for a meeting with Trump in December, told reporters that Trump was indeed a "great negotiator," but that the Mexican people should not be afraid of him. Slim's understanding of Trump, he said, was largely based on his reading of Great Again: How to Fix Our Crippled America, a copy of which Slim read from during his press conference.

Slim was critical of Trump's plan to pay for his border wall with an import tax, stating that any tariffs would end up being paid by American consumers. He said that Trump had a desire to "return to the past" where the United States was an industrial power, describing such a move as a bad idea.

Slim said that he thinks Mexico is in a strong position for negotiations and offered to join President Nieto in discussions with Trump. He also said that he was supportive of the way that Nieto has handled negotiations thus far.

"We should not be scared of Trump or think things will necessarily go badly," Slim said. "Trump is not the Terminator, he is the negotiator."

Mexico's strong negotiating position is in part thanks to Trump, said Slim, who remarked that he hadn't seen the Mexican people so politically united in three decades.

Slim advised Mexico against overreacting to the current situation, saying that the "hyperactivity" would calm with time. He advised against boycotts of U.S. products.

The billionaire said that Mexico's primary goals should be to help Mexicans who are currently residing in the United States and to develop its domestic economy, noting that investment, economic opportunity, and jobs are the "wall" Mexico should build during the age of Trump.