OTTAWA—Canadian Prime Minister Justin Trudeau, on the eve of an Ottawa summit with U.S. and Mexican leaders, pointed to the North American example of economic integration and warned of risks posed by a growing tide of protectionism and nationalism underscored by last week's Brexit vote.

"Better collaboration, better partnerships are a path to prosperity," Mr. Trudeau said at a joint press conference in Ottawa with Mexican President Enrique Peñ a Nieto, ahead of Wednesday's North American leaders' summit in which President Barack Obama will also participate.

Mr. Trudeau and Mr. Peñ a Nieto unveiled measures aimed at boosting Canada-Mexico ties, with Canada agreeing to lift a contentious requirement on Dec. 1 that required Mexicans visiting Canada to obtain a visa.

Mexico, meanwhile, agreed to open up its market to Canadian beef exports.

"We have a shared vision, and we really believe in regional integration," said Mr. Peñ a Nieto. "We have a shared vision, and we really believe in regional integration," said Mr. Peñ a Nieto. "Working as part of a team will allow our societies to develop further, and better."

North America is "a compelling example we want to showcase at a time unfortunately people are prone to turning inwards -- which will be at the cost of economic growth," Mr. Trudeau said.

Mr. Trudeau is set to host the summit at a turbulent time for the developed world, as it deals with the fallout from the U.K. vote to leave the European Union. Most stock markets rebounded Tuesday after days of steep declines, which wiped out $3 trillion from global stock markets, as traders worry about the economic and political consequences from the vote.

The summit's agenda will now pivot to tackle Brexit's fallout, and how the countries could coordinate efforts to insulate themselves, according to a briefing by U.S. officials. "There are opportunities to highlight the significance of North America," said Mark Feierstein, senior director for western-hemisphere affairs at the National Security Council.

Canada is the leading market for U.S. exports, while Mexico ranked second. On the import side, Canada and Mexico ranked second and third, respectively.

The Brexit victory comes as the U.S. presidential election cycle in is full swing, which has featured Republican presumptive nominee Donald Trump championing greater border and immigration controls, and skepticism about trade pacts such as the North American Free-Trade Agreement.

"The North American leaders realize the whole framework of continental integration and cooperation could be in jeopardy," said Eric Miller, head of Washington-based Rideau Potomac Strategy Group, a consultancy that specializes in North American trade issues.

Besides Wednesday's meeting of North American leaders, Mr. Obama will meet with European leaders next week during a summit among members of the North Atlantic Treaty Organization about next steps, such as what the European Union can do to reduce the risk other states will follow in U.K.'s footsteps.

U.S. officials said the three leaders would also address a range of issues that go beyond the economy, such as peacekeeping, drug trafficking and refugees. The three countries will also agree to boost clean-energy production, while Mexico will join Washington and Ottawa in a formal pact to reduce methane emissions by up to 45% by 2025, U.S. officials said.

Write to Paul Vieira at paul.vieira@wsj.com

(END) Dow Jones Newswires

June 28, 2016 14:45 ET (18:45 GMT)