Canada the U.S. and Mexico are close to an agreement in principle on the future of North America Free Trade Agreement, CBC News has learned.

A source with direct knowledge of the negotiations between the three countries said a few more weeks of talks may be all that is needed, but an announcement could come before the leaders of all three countries meet next week at the Summit of the Americas in Peru.

The source said the agreement could take the form of a positive statement on talks, or a framework to move forward that would primarily focus on the auto sector, but could also include other key aspects of the free trade agreement.

The source said Friday's talks in Washington, D.C. have been productive, but more work needs to be done.

Foreign Affairs Minister Chrystia Freeland said Friday that the NAFTA negotiations recently entered "a new, more intensive phase of engagement" — but would not say how close Canada, Mexico and the U.S. are right now to signing a deal.

Freeland and the two top trade officials from the U.S. and Mexico meet in D.C. Friday to continue work on a revised trilateral trade deal, in what could be the final stretch of the NAFTA renegotiation process.

Freeland has said in recent weeks the tone of the talks became more positive recently, and that shift in tone has carried forward into recent bilateral and trilateral meetings with U.S. Trade Representative Robert Lighthizer and Mexican Economy Minister Ildefonso Guajardo.

"Intensive engagement is going to continue in the days to come. We've had some good conversations over the past couple of days," she said.

"We talked about many, many tangible things today."

Foreign Affairs Minister Chrystia Freeland says Canada has moved on to a more intensive stage of NAFTA negotiations, but she remains coy on how soon a deal might be signed. 0:44

Asked whether there could be an announcement on a deal in the next 12 hours, she would only say, "I think I've been clear about where we are, which is two days of good, constructive meetings with a positive tone.

"We are going to continue working hard in the days to come."

Freeland added she'll stay in the U.S. capital "for a little while longer."

Speaking in Alberta, Prime Minister Justin Trudeau said he was pleased by the number of chapters that have been closed already during the NAFTA negotiations, but would not say when he expects a final deal.

"We are going to keep going and demonstrate that we take this issue very seriously," he said. "We'll continue to defend Canadian jobs, but we're hopeful to get positive news in the coming times."

PM asked about NAFTA talks during a stop in Wood Buffalo Alberta 1:19

Lighthizer, who was picked by U.S. President Donald Trump for the job largely on the strength of his protectionist credentials, has said there must be progress on the deal before Mexico and the U.S. become entangled in potentially fractious election campaigns later this year.

The Mexican presidential election is in July — an anti-Trump candidate is leading in public opinion surveys there — and Americans head to the polls for midterm elections in November.

Trump, who has repeatedly threatened to pull his country out of the negotiations if he cannot secure major concessions from Canada and Mexico, said yesterday during a stop in West Virginia that a deal could be coming soon.

"We'll have something — I think — fairly soon. It'll be very interesting," he said. "I said to them, 'Let's not rush it, let's take it nice and easy, let's get it done right or we'll terminate.'"

Trump said he has faced pressure from some officials in his administration to reach a deal ahead of the Summit of the Americas meeting in Peru next week.

Even if the three political leaders reach an agreement-in-principle during these talks in Washington, the final details of the new NAFTA deal would still have to be worked out by trade negotiators.

Steve Verheul, Canada's chief negotiator, said last week there were still major differences between the three sides over government procurement and dispute resolution.