"We want to ensure that for businesses and individuals, that there is as smooth a changeover, when the United Kingdom leaves the European Union, as possible; we want to see as little disruption to economies and to people's lives," she said.

The two leaders also discussed their joint interest in resolving the aerospace trade dispute, in which Boeing alleges Canadian government subsidies to Bombardier led to a deal to sell 75 jets to Delta Airlines for a lower price.

Bombardier is both a major Canadian company and a significant employer in Northern Ireland, with 5,000 workers in Belfast making up about 10 percent of the area's manufacturing jobs.

May said she'll reiterate Bombardier's importance to Northern Ireland to Trump later this week.

Trudeau said Canada will continue to stand up for jobs against "unwarranted actions" by Boeing that are in its own "narrow interest," not the principle of open trade.

"We won't do business with a company that's trying to sue us," Trudeau said of Canada's potential purchase of Boeing fighter jets.

A preliminary decision from the US Commerce Department on the dispute is expected next week. The final decision, which could include financial penalties.