Story highlights The fourth round of negotiations on NAFTA are getting underway

Trump pledged to end or renegotiate NAFTA during the 2016 campaign

Washington (CNN) Trump administration negotiators are bringing an aggressive position on trade to the North America Free Trade Agreement negotiating table, demanding several provisions that some worry will sink the deal and give President Donald Trump a reason to scrap the agreement entirely, business leaders and sources with knowledge of the proceedings tell CNN,

With the fourth round of negotiations on NAFTA getting underway and Canadian Prime Minister Justin Trudeau meeting Trump at the White House on Wednesday, sources say the Trump administration will propose tightening rules on the origins of car parts, push to implement a sunset provision on the deal and urge an end to the process used to resolve conflicts between nations and businesses.

White House aides declined to confirm that these proposals were on the table, noting that negotiations are far from over, but representatives from the business community are worried that such demands will make it impossible for Mexico and Canada to agree to a revamped deal. If they walk away, sources say, the lack of an agreement could give Trump a reason to end the trade deal entirely.

Tom Donohue, president of the US Chamber of Commerce, said on Tuesday in Mexico City that he worried about the "several poison pill proposals still on the table that could doom the entire deal."

Negotiators led by United States Trade Representative Robert Lighthizer, Donohue said, have pushed for a sunset clause that would allow any country to terminate the deal after five years and tighten rules on where parts that eventually go into finished products can be purchased.

Read More