Canada and the United States will make a final push to iron out differences on a pact to modernize the North American Free Trade Agreement (NAFTA) by a Friday deadline set by President Donald Trump, but the atmosphere soured late on Thursday according to a media report.

U.S. Trade Representative Robert Lighthizer and Canadian Foreign Minister Chrystia Freeland were unable to clinch a deal despite meeting late into the evening on Thursday. They will reconvene on Friday morning, with Mexico on standby to return to talks aimed at ending a year of hard-fought three-way negotiations.

But Canadian officials are now expressing concern that a final NAFTA deal will not be concluded on Friday, the Globe and Mail reported, citing a source familiar with the situation.

The report said Lighthizer refused to budge despite repeated efforts by Freeland to offer concessions to maintain an independent trade dispute mechanism in a revamped trade deal, which has been the biggest sticking points for Canadians.

Read more in Reuters.