A former Mexican president has a warning for Prime Minister Justin Trudeau: Don't abandon our country in NAFTA talks like some modern-day "Judas."

Vicente Fox warns that would be a mistake.

Fox told CTV News that it wouldn't do any good if Canada ditched Mexico in pursuit of a one-on-one trade deal with the U.S., in the misguided belief President Donald Trump would go easier on Canada.

Fox made his case using a biblical metaphor — urging Prime Minister Justin Trudeau not to behave like the apostle who sold out Jesus Christ.

NAFTA negotiations have resumed in Mexico and this round is doing little to provide optimism on a deal getting done. The updated list of trade objectives released by U.S. negotiators includes positions both Canada and Mexico have said they wouldn't support. It's not just the trade partners that stand to lose out either; U.S. farmers are lobbying just as hard to keep NAFTA in place 4:42

"He might, like Judas, give us a strike and go with the United States and leave us aside," Fox told the network, in an interview airing Sunday night.

"I warn Trudeau, and I warn Canada, you will not make it [better without Mexico]."

The Canadian government has repeatedly said it's committed to working trilaterally to renew NAFTA as a three-country agreement. However, the Canadians have also raised eyebrows in Mexico by occasionally making more ambiguous comments: some Canadian officials have at times suggested they're open to both bilateral or trilateral deals.

Former prime minister Stephen Harper accuses Justin Trudeau's Liberal government of not taking trade negotiations seriously enough, in a leaked memo titled 'Napping on NAFTA' 2:12

Trump says he could do one or the other.

Former prime minister Stephen Harper, in a memo earlier this year to associates that was obtained by The Canadian Press, appeared to favour the one-on-one approach. Harper suggested Trump had few trade complaints about Canada, and he said some Americans found it mystifying that the Canadian government remains so attached to a trilateral deal with Mexico.

'Win-win-win for all 3 countries'

Proponents of the three-country approach say it makes sense for several reasons: the continent has integrated supply chains for products like autos, some of the strongest defenders of trade in U.S. politics are from southern Mexican border states, and, they say, there's no guarantee anyway that Trump would go soft in a separate negotiation with Canada.

In the CTV interview, Fox also did what he has done repeatedly over the last two years: Blast Trump. Using a few four-letter profanities, the former Mexican president called Trump a destroyer, pitting America against the world.

Trudeau and current Mexican President Enrique Pena Nieto are seen during a bilateral meeting at the APEC Summit in Da Nang, Vietnam, on Nov. 10. (Adrian Wyld/Canadian Press)

Canadian officials were puzzled by the Judas comment. They pointed out that there's been no move whatsoever to isolate Mexico.

"We are committed to modernizing NAFTA as a strong trilateral agreement that is a win-win-win for all three countries," said Alex Lawrence, a spokesman for Foreign Affairs Minister Chrystia Freeland.

"Prime Minister Trudeau and Mexican President Pena Nieto spoke about the strength of our relationship and our shared goals as recently as last week in Vietnam, as well as during the Prime Minister's visit to Mexico City last month."