U.S. President Barack Obama and Mexican President Enrique Pena Nieto also took swipes at U.S. Republican presidential candidate Donald Trump, who has vowed to renegotiate or scrap the North American Free Trade Agreement (NAFTA) if he wins November's election.

"The integration of national economies into a global economy: that's here, that's done," Obama told a news conference at the end of a summit dubbed the "Three Amigos".

"And us trying to abandon the field and pull up the drawbridge around us is going to be bad for us," he said after the talks, hosted by Canadian Prime Minister Justin Trudeau.

Trump says free trade has been disastrous, costing thousands of U.S. jobs and depressing wages.

Similar complaints were heard in Britain ahead of a surprise referendum vote last week to leave the European Union and its free trade area.