Trump's decision comes as an investigation mounts at home into whether his presidential campaign colluded with Russia in the 2016 election and as Congress presses for tougher sanctions against Moscow.
Trio at loggerheads sign new trade deal
US President Trump, Canadian Prime Minister Justin Trudeau and Mexican President Enrique Peña Nieto signed a new US-Mexico-Canada Agreement — or USMCA — in Buenos Aires.
The trio, who have often been at loggerheads on trade, used the G-20 Summit to resolve the trade dispute with America's closest neighbours.
Trump spent more than a year pushing the leaders of Canada and Mexico into agreeing to a rewrite of North American trade rules.
"This has been a battle, and battles sometimes make great friendships," Trump said at the start of the signing ceremony.
Saying that all three countries will benefit from the deal, Trump said of the USMCA, "It is probably the largest trade deal ever made."
Trump now faces what could prove a more formidable foe: the US Congress, which must ratify the agreement.
He says the parties have "taken a lot of barbs and a little abuse" during the renegotiation.
Saudi Crown Prince meets with G20 leaders
Saudi Crown Prince Mohammed bin Salman has talked with world leaders at a Group of 20 summit clouded by concerns about the gruesome killing of Saudi journalist Jamal Khashoggi.
Journalists saw the crown prince speaking with French President Emmanuel Macron and others at the summit venue on Friday in Buenos Aires.
Macron's office wouldn't comment on what they discussed.
On the eve of the summit, the French president called fors international involvement in the investigations into Khashoggi's killing in the Saudi Embassy in Istanbul last month.
EU leaders urged G20 participants to address concerns about journalist safety and the Saudi-backed war in Yemen.
US intelligence agencies have concluded the crown prince ordered Khashoggi's killing. Saudi Arabia has denied that.
Trump has said he won't be meeting with the Crown Prince at the G20.
