"Revamping the new trade agreement was aimed to preserve the view of an integrated North America with the firm belief that together we are stronger and more competitive", he said in remarks translated from Spanish. The President needs to talk to Congress on this.
"Just so you understand, when I do that - if for any reason we're unable to make a deal because of Congress then Congress will have a choice" of the new deal or returning to trade rules from before 1994 when NAFTA took effect, he said.
Trump had vowed to revamp NAFTA during his 2016 presidential election campaign.
The leaders of Canada, Mexico and the USA signed a revised North American free trade pact Friday on the margins of the G20 summit in Argentina that is set to govern more than $1.2 trillion in regional commerce. Trump has repeatedly criticized NAFTA, calling it "the worst trade deal in history". While Congress does need to approve the implementation of a trade deal, some experts say that the Trade Act of 1974 gives to president authority to pull out of such deals on his own. The U.S. does about a $1 trillion worth of business each year with the two countries, and Canada (second) and Mexico (third) are America's most significant trade partners.
On Sunday, Henry Connelly, a spokesman for Pelosi, told the New York Times that it was "disappointing but not surprising" that Trump was trying to force Congress to approve the new deal.
Shortly after Friday's signing, U.S. Trade Representative Robert Lighthizer insisted that the deal was negotiated with bipartisan support from both Democrats and Republicans, and expressed confidence it would survive the congressional approval process.
In a blog entry posted shortly after the agreement was signed Friday, Cato Institute trade analyst Simon Lester appeared to anticipate Trump's move - although he acknowledged it would have made a lot more sense if the Republicans still had control of Congress.
The leaders of the three countries agreed on a deal in principle to replace NAFTA, which governs more than United States dollars 1.2 trillion of mutual trade, after acrimonious negotiations concluded on September 30.