TOLUCA, Mexico - President Barack Obama on Wednesday touted the shared "commitment to trade" between the U.S., Mexico and Canada, while trying to reassure America's neighbors that he would seek to expand their economic alliances despite political resistance from his own Democratic Party.

"We have every incentive to make this work," Obama said during remarks to North American business, civil society and education leaders.

Obama spoke alongside Mexican President Enrique Pena Nieto and Canadian Prime Minister Stephen Harper, who joined him in the industrial center of Toluca for the one-day North American Leaders' Summit. This year's meeting coincides with the 20th year of the North American Free Trade Agreement among the three countries, a deal that has vastly expanded cross-border commerce in the region but which remains a contentious issue in the United States over its impact on jobs and on environmental protections.

Trade experts say the agreement is due for an upgrade to take into account the current globalized environment and to address issues not touched in the original pact. But rather than reopen NAFTA, the three countries are instead relying on negotiations underway to complete the Trans-Pacific Partnership, a trade bloc of 12 countries in the Americas, Asia and the Pacific.

The Obama administration is hoping those negotiations are completed this year. The U.S. is also in the midst of negotiations over a Trans-Atlantic Trade and Investment Partnership with the European Union. But Obama is facing stiff election-year resistance from Democratic leaders over his desire to get "fast track" trade authority, which would require Congress to give yes-or-no votes on the trade agreements without the opportunity to amend them.

While Obama did not directly address the opposition from lawmakers during his public comments on trade, he said each leader grapples with their country's "parochial interests."

"That will express itself politically, and we have to be responsive to our own constituencies," the president said.

Keeping with the trade focus of the trip, Obama signed an executive order while traveling on Air Force One intended to speed up the process for approving import or export cargo. The order directs the government to finish a new electronic system to allow companies to submit their documentation to the government without paper forms.

Harper and Pena Nieto echoed Obama's comments on the central role trade plays in the relationship between the North American countries. The Mexican leader challenged business and civil society leaders to help make "North America a region more competitive and more prosperous as merited by our citizens." And the Canadian leader declared that, "Our economic futures in this continent are increasingly linked."

In a nod to the controversial Keystone XL pipeline that Canada is urging Obama to approve, Harper also noted that TransCanada, the company working to build the pipeline, was among the businesses represented at the summit.

Following their comments to the business community, the three leaders were to hold a private summit meeting, followed by a joint news conference.

Obama and Harper held a brief one-on-one meeting earlier Wednesday, strolling through Toluca's lush botanical gardens. Canadian officials have voiced frustration at the amount of time the Obama administration has taken to decide whether to approve the Keystone pipeline, which would carry oil from tar sands in western Canada 1,179 miles to Nebraska, where existing pipelines would then carry the crude to refineries on the Texas Gulf Coast.

A Nebraska judge on Wednesday struck down a law that allowed the pipeline to proceed through the state, a victory for opponents who have tried to block the project.

Obama and Pena Nieto also met separately Wednesday before the three-country summit opened. The U.S. president had been expected to be quizzed by his counterpart on his prognosis for overhauling U.S. immigration laws, an issue of intense interest for Mexicans both in Mexico and in the United States. While White House officials remain hopeful Congress can complete immigration legislation this year, chances of passage in the Republican-controlled House this year are dimming.

The summit also unfolded against other tensions, including revelations that the National Security Agency spied on Pena Nieto before he was elected and gained access to former Mexican President Felipe Calderon's email system when he was in office.

Events elsewhere in the world also competed for Obama's attention. The president condemned the violence that erupted in Ukraine as the government of President Viktor Yanukovych cracked down on protesters and warned that there would be consequences if the clashes continued.

Officials said the U.S. was weighing its options against those responsible for the violence, including consulting with the European Union on the use of sanctions.

Obama arrived in Toluca, about 40 miles west of Mexico City, Wednesday afternoon. He planned to spend just about nine hours on the ground, with Air Force One scheduled to depart Mexico shortly after the evening news conference.