Central to the discussions Sunday was an effort to secure some sort of assurance that would allow Canada to avoid the dreaded Section 232 tariffs on steel, aluminum and auto exports, which U.S. President Donald Trump has either threatened or already imposed on national security grounds.
A USA official said a few minutes earlier that the United States and Canada were "very close" to a deal.
Canada has agreed to sign on to a trade deal between US and Mexico, preserving the three-country North American Free Trade Agreement after more than a year of tortuous negotiations, a USA official and a Canadian official told CNN late Sunday.
The U.S., in turn, has agreed to preserve the "Chapter-19" mechanism for resolving disputes over anti-dumping and anti-subsidy duties, but with some limitations to address American concerns about the tool usurping domestic courts and undermining its sovereignty, the person said.
President-elect Andrés Manuel López Obrador of Mexico said on Friday that Trudeau had appealed to him to help pave the way for a three-nation deal and that he would insist that a revised Nafta include Canada.
U.S. President Donald Trump has said he wants to go ahead with a revamped NAFTA - with or without Canada. MacNaughton said he wasn't sure if they would reach an agreement by Monday but said he was cautiously optimistic.
Mexican foreign secretary Luis Videgaray said: "It's a good night for Mexico and for North America".
"We look forward to further deepening our close economic ties when this new agreement enters into force", the statement reads.
Earlier in the evening, President Donald Trump was briefed on the almost finalized negotiations by U.S. Ambassador Robert Lighthizer and White House adviser Jared Kushner.
Trump complained about the behavior of Canadian officials, and said he rejected a meeting with Prime Minister Justin Trudeau, although Trudeau's office said no meeting was planned.
It's lights out across Okinawa; Honshu braces for big typhoon：The Asahi Shimbun
This powerful typhoon is now equal to a Category 3 major hurricane in the Atlantic or East Pacific Ocean. I stepped outside the city hall in the afternoon, and the rain was swirling in very strong wind.
The agreement will boost United States access to Canada's dairy market and protect Canada from possible USA auto tariffs, two sources with direct knowledge of the talk told Reuters.
Most of the "substantive work" has been completed, with a "handful" of details remaining, the newspaper reported.
"It's a great win for the president and a validation of his strategy in the area of worldwide trade".
Two senior government officials confirmed the meeting.
Canada and Mexico are two of the biggest trading partners with the United States.
A senior U.S. administration official said the final rewrite is a "fantastic agreement" and he called it "a big win for the United States, Mexico and Canada".
But the US and Canada had trouble dealing with other areas in the pact, including Canada's dairy industry, its insistence on a strong dispute settlement mechanism and concerns about intellectual property and culture.
Canadian government officials and outside stakeholders from industry and labour groups who were consulted throughout a weekend of intense talks said negotiators had made "progress" Sunday on key points that had been in dispute. It was unclear, however, whether Mr. Trump had authority from Congress to pursue a revamped NAFTA with only Mexico, and some lawmakers said they wouldn't go along with a deal that left out Canada. He said he didn't know if a deal would be reached Sunday.
In public, Canadian bank executives were staunchly hopeful that Canada, the USA and Mexico would ultimately reach an agreement, but avoided weighing in on specifics.
Daniel Ujczo, a trade attorney with the Dickinson Wright law firm who has followed the talks closely, said he expects the USA to get more access to the Canadian dairy market.