Canada, which is a part of NAFTA, was not part of the announcement.
Mexican president tells trump on call it is Mexico wish that Canada now be incorporated into the deal - Reuters witness.
President Donald Trump had pulled the United States out of the NAFTA pact claiming it was unfair to Americans.
For that to happen, US Congress must be notified 90 days in advance, which means the administration must send the notice by the end of the week. A month ago, representatives from both the US and Mexico returned to the table after Mexico's elections forced a two-month hiatus on negotiations.
"It will be necessary for Canada to rejoin the negotiations and for an agreement to be reached among all parties before a judgement can be made".
The deal with Mexico involves the automobile industry, but does not include other areas of contention, The New York Times reported.
In the room with Trump were U.S. Trade Representative Robert Lighthizer, Mexico's Foreign Minister Luis Videgaray Caso, and Mexico's Economic Minister Ildefonso Guajardo.
Pena Nieto joined by phone, and thanked Trump, calling the breakthrough on NAFTA "very positive for the United States and Mexico", and looked forward to the trilateral agreement.
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"He's amazed the party would think it's a good idea to replace a prime minister doing a good job", Mr Pyne said. Turnbull has said he will not stand if the Liberal Party parliamentarians back a motion for a leadership vote.
Adam Austen, a spokesman for the Canadian foreign minister, Chrystia Freeland, said: "Canada is encouraged by the continued optimism shown by our negotiating partners".
"There are still issues with Canada but I think they could be resolved very quickly", the official said.
None of that stopped Trump from giving the impression on Monday morning that he was "terminating" NAFTA "and going into this deal" with Mexico.
But at least initially, it looks like at least a tentative public-relations victory for Trump, the week after his former campaign manager was convicted on financial crimes and his former personal attorney implicated him in hush money payments to two women who say they had affairs with Trump.
Still, an accord between the US and Mexico is the biggest development in talks that began a year ago, punctuated by Trump's repeated threats to quit altogether.
Advisers of incoming President Lopez Obrador hailed the new deal, saying it represented progress on energy and wages for Mexico's workers.
But pressed as to whether Mexico is willing to enter a bilateral deal with the USA, a senior White House official on the same call dodged.
Still, any new agreement is far from final.
Trump used his announcement on Monday to gripe about Canadian tariffs on American dairy products.