Leaders of the US, Canada and Mexico on Friday signed a new trade deal to replace the North American Free Trade Agreement (Nafta) that Donald Trump touted as a huge win for the American economy.
After 14 months of acrimonious negotiations, the US-Mexico-Canada Agreement (USMCA) was signed at an event in the Argentinian capital on the sidelines of a Group of 20 summits of advanced and developing economies.
Trump called the new deal the "most significant and largest" in US history, CNN reported.
Standing between outgoing Mexican President Peña Nieto and Canadian Prime Minister Justin Trudeau at a press conference, the US President said: "We worked hard on this agreement, it's been long and hard. We've taken a lot of barbs and a little abuse, but we got there."
He said the deal would give American farmers greater access to markets for their agricultural products, "something we've been wanting to for many years".
Trump also said the deal would transform the American auto industry, promoting fair competition and high wages.
The signing of the new USMCA trade deal does not mean it goes into effect as it still requires Congressional approval in Washington, where key members of both political parties have expressed significant concerns.
Cautiously welcoming the ceremonial signing, Trudeau said: "The new North American free trade agreement maintains stability for Canada's entire economy, the stability that's essential for the millions of jobs and middle-class families across the country that rely on strong relationships with our neighbours. That's why I'm here today."
But he cast doubt on the US leader's optimism, pointing to plant closures by General Motors in North America as "a heavy blow" and taking the opportunity for a jibe at the US leader's protectionist policies, CNN said.
"And Donald, it's all the more reason why we need to keep working to remove the tariffs on steel and aluminium between our countries."
In the deal, Canada won concessions including a dispute resolution system for companies that feel unfairly targeted with taxes.
It will also receive exemptions from any future American tariffs on 2.6 million imported passenger vehicles. In return, Canada agreed to, among other things, Trump's repeated demands that it cracks open its dairy market, the New York Times reported.
However, Trump's tariffs on Canadian metals remain in place, testing the relationship between Canada and its biggest and most important trading partner.
A massive security operation was underway for the G20 summit. The leaders with whom Trump will speak in bilateral meetings include Indian Prime Minister Narendra Modi, German Chancellor Angela Merkel, Japanese Prime Minister Shinzo Abe, South Korean President Moon Jae-in and Turkish President Recep Tayyip Erdogan.
The US leader cancelled a meeting with Russian President Vladimir Putin in protest over Moscow's seizure of Ukrainian naval boats.
He will remain in Buenos Aires until Saturday night, leaving after a working dinner with Chinese President Xi Jinping, in which both could reach an agreement to stop an ongoing trade war between the two nations.
World leaders will be holding discussions later on Friday amid Kiev-Moscow tension and Washington's trade row with Beijing. Climate change was expected to be another major sticking point in the talks.
The summit was also a diplomatic test for Saudi Crown Prince Mohammed bin Salman amid continuing questions about possible involvement in the murder of journalist Jamal Khashoggi in Turkey.
(With inputs from agencies.)