Prime Minister Stephen Harper, Mexican President Felipe Calderon and U.S. President Barack Obama sit together for a working dinner in Guadalajara on Sunday. (Alfredo Guerrero/Reuters)

Leaders of Canada, Mexico and the United States are discussing swine flu, the global economic downturn, drugs, travel and trade at the so-called "Three Amigos" summit in Guadalajara, Mexico, on Monday.

U.S. President Barack Obama, Mexican President Felipe Calderon and Prime Minister Stephen Harper began the two-day summit in Mexico on Sunday with a dinner.

The meeting in the western colonial city is the first for the three leaders since Obama took office.

Dozens of riot police manned roadblocks around the city to keep protesters at bay. About 400 people marched outside the North American Leaders Summit on Sunday.

Prime Minister Stephen Harper answers questions following his meeting with Mexican President Felipe Calderon on Sunday. (Adrian Wyld/Canadian Press)

A parallel meeting between anti-globalization, environmentalist and social activists is also being held in Guadalajara.

The North American leaders are expected to look ahead to the fall and the handling of the swine flu pandemic during the trilateral discussions on Monday.

Analysts have said the leaders will likely discuss the impact of closing borders or restricting travel if the flu's spread makes those measures necessary. But health experts have said that restrictions would likely be pointless in attempting to contain the flu's spread.

John Brennan, Obama's chief homeland security aide, said a key goal for the Obama administration at the meeting was to ensure all three countries ensure their citizens are fully informed about how to mitigate the spread of the virus.

The meeting in Mexico is important in further linking health officials and readying vaccine and antiviral supplies, Brennan said.

"There are people who are going to be getting sick in the fall and die," he said. "We want to make sure that we do everything possible to ensure the continuation of commerce, transportation and trade between the three countries."

At the conclusion of the meeting the three leaders are expected to release a joint statement regarding how they will "tackle the H1N1 challenge," Brennan said.

The summit, which is expected to only span about 17 hours is scheduled to conclude shortly after noon and will be followed by the leaders' joint statement.

Visa requirements

Harper is also expected to have continued to address concerns raised by Calderon about Canada's requirement for Mexican visitors to have travel visas.

Ottawa announced last month that travellers from Mexico and the Czech Republic will need visas to enter Canada because of skyrocketing numbers of refugee claimants from the two countries.

Harper has said the visa requirement is necessary because of Canada's refugee system, which can't handle the thousands of refugee claims from Mexicans.

The visa requirement will remain in place until Canada's refugee system is reformed, Harper said after meeting with Calderon ahead of the summit talks.

"This is not the fault of the government of Mexico," Harper said. "Let me be clear about this. This is a problem in the Canadian refugee law that encourages bogus refugee claims."

Gang violence

The U.S. and Mexico were also expected to discuss the violent Mexican gangs dominating the drug trade on both sides of the border. Mexican gangs are blamed for the flow of illegal drugs in North America and for 6,000 deaths last year.

Calderon has expressed concern to Obama about the implementation of a three-year U.S. drug-fighting plan. On Sunday, Harper pledged $400,000 to send 30 RCMP officers to Mexico to train hundreds of Mexican police in a variety of areas, including undercover tactics.

The "Buy American" policy and U.S. stimulus spending was also expected to be on Monday's agenda.

The U.S. neighbours want Obama to explain where America's economic recovery is going, because both countries saw their own fortunes fall as a result of problems in the U.S.

With files from The Canadian Press and The Associated Press