Bloomberg News on Sunday denied being the source of an off-the-record interview remark made by President Donald Trump that complicated already tense negotiations between the U.S. and Canada over the contours of a new North American Free Trade Agreement.

An 11th hour firestorm erupted late last week in the wake of the president's sit down with Bloomberg for an on-the-record interview. However, a portion of Trump's remarks that were not for attribution or publication — in which he suggested he wouldn't grant Canada any concessions at all — were somehow obtained and reported by Toronto Star.

On Sunday, Bloomberg Washington bureau chief Craig Gordon said the organization neither published or authorized the release of any of the off-the-record material from Trump's interview. "When we agree that something is off the record, we respect that agreement," Gordon wrote on Twitter.

The leak was highly unusual, given journalistic rules of engagement governing off-the-record material. Usually, if a source grants an interview but requests that certain portions not be published or attributed directly to them, reporters must abide those terms.

Trump, who is consistently at war with the media, denounced the leak on Friday as an example of "more dishonest reporting," and called on Bloomberg to apologize.

Trump tweet

Trade talks between the United States and Canada will kick off again Wednesday, after the two sides ended Friday's tense negotiations without a deal.

"If we don't make a fair deal for the U.S. after decades of abuse, Canada will be out. Congress should not interfere with these negotiations or I will simply terminate NAFTA entirely & we will be far better off," the president said on Twitter Saturday, blasting the trade pact as one of "the worst deals ever made."