Negotiators reached a consensus before the deadline of midnight on Sunday, meaning the new agreement can be submitted to U.S. congress the required 60 days before being signed.
The agreement "will give our workers, farmers, ranchers and businesses a high-standard trade agreement that will result in freer markets, fairer trade and robust economic growth in our region".
USA and Canadian trade negotiators hammered out the finer details of a NAFTA rework over the weekend, ahead of the US' self-imposed deadline of midnight Sunday (04:00 GMT).
The US and Canada came to an agreement Sunday to tweak key pieces of the North American Free Trade Agreement, known as NAFTA.
An announcement was "imminent" as of Sunday night, with just hours to go before the USA -imposed midnight deadline, the official said.
If the deal is ratified by the three countries' legislatures, their heads of state - US President Donald Trump, Canadian Prime Minister Justin Trudeau and Mexico's outgoing president Enrique Pena Nieto - will sign it on November 30, reported Mexican TV network Televisa.
"Everybody's negotiating in good faith right now as we speak", Navarro said on Fox News just before 11 a.m.
But the deal failed to resolve United States tariffs on Canada's steel and aluminum exports, the Canadian sources said.
United States negotiators reached a bilateral deal with Mexico late last month.
And on the matter of Section 232 tariffs, Trump's trade weapon of choice, US officials say the new deal doesn't address them directly, since they are a matter for the Department of Commerce.
The deal represents a win for Trump, who has derided Nafta for years and threatened to pull the USA from the pact if it was not rewritten in Washington's favour.
A big worry now appears to be Trump's threat to impose a 25 per cent tariff on the Canadian automotive industry (that, significantly, could be imposed even if a NAFTA 2.0 deal were to be reached).
Negotiators for the United States and Canada were able to overcome major sticking points between the two countries, including Canada's protection of its dairy market and a system for settling trade disputes.
Under U.S. trade law, the administration was required to publish the text by the end of September.
And with that, he said he would talk to reporters Monday.
The deal reportedly grants USA farmers access to the heavily protected dairy market.
U.S. Trade Representative Robert Lighthizer and White House adviser Jared Kushner have been updating Trump throughout Sunday on the talks, a U.S. source familiar with the discussions said. It will also be called the "United States-Mexico-Canada Agreement", or USMCA.
The access level is reportedly identical to what Canada agreed to give up as part of the Trans-Pacific Partnership (TPP), out of which Trump pulled the USA early in his tenure.
The deal also requires greater use of American and Mexican steel, aluminum, glass, and plastics.
Ottawa and Washington remained at odds over Canada's subsidized dairy sector, and the dispute resolution provisions in NAFTA. Companies and business groups, including the US Chamber of Commerce, have repeatedly called on Trump to ensure Canada remains part of the pact, which has become critical for industries across North America, including automakers, agriculture, and manufacturers.