OTTAWA - As NAFTA negotiations resume this week, Canada and Mexico have been taking a hard line against the so-called "poison pills" the U.S. has put forward during their increasingly acrimonious talks.

But sources say the two countries plan to give the Trump administration a rough ride in an area that hardly seems contentious: language from the original Trans-Pacific Partnership.

Canada and Mexico, the sources say, are in no hurry to adopt the significant portions of TPP text that American negotiators have brought to the NAFTA table.

President Donald Trump withdrew the U.S. from the massive 12-country Pacific Rim trade deal in January, but that hasn't stopped the U.S. from using it as a template to bring the 23-year-old NAFTA into the 21st century, updating it for the digital age and e-commerce.

The sources, who spoke on condition of anonymity because of the sensitivity surrounding the NAFTA talks, say Canada has no incentive to give the U.S. an easy win on the proposed TPP boilerplate.

That's because the U.S. has been putting forward untenable positions -- the so-called non-starter "poison pills" in a five key areas -- that some observers have suggested are designed to sabotage the talks and kill NAFTA outright.