Canadian Foreign Minister Chrystia Freeland (Photo: EPA)

Freeland said she spoke with US Trade Representative Robert Lighthizer over the weekend after their talks ended on Friday, and their teams have had a lot of contact since then. "We agreed that it would be useful to continue talking today, so we're back for more negotiations," Freeland told reporters, adding that the conversations over the weekend continued to be constructive and productive.

In the last two weeks, officials from the US and Canada pushed the negotiations toward an amended NAFTA. US President Donald Trump has threatened to withdraw from the agreement because it harms US workers.