Mexican president-elect Felipe Calderon used his visit to Ottawa Thursday to highlight Mexico's opposition to the barrier the U.S. is building along the Mexican border.

As Calderon and Prime Minister Stephen Harper discussed cooperation in North American trade, President George W. Bush was signing the Secure Fence Act of 2006, a bill that authorizes the construction of more than 1,000 kilometres of fence between the U.S. and Mexico.

"It is deplorable to go ahead with this decision of the wall at the border," Calderon said Thursday morning after a meeting in Ottawa. "The wall will not solve any problem.

"Humanity made a huge mistake by building the Berlin Wall and I believe that today the United States is committing a grave error in building the wall on our border. It is much more useful to solve common problems and foster prosperity in both countries."

The wall will cause more, not fewer, Mexicans to die trying to cross the border, Calderon predicted. More than 400 people died trying to get into the U.S. illegally last year.

Calderon hoped to get Harper's support for Mexico's opposition to the fence, which the U.S. hopes will reduce the flow of illegal immigrants. There are between 11 to 12 million illegal immigrants who have entered the U.S. from Mexico.

But Calderon, who won Mexico's presidential election in July by 233,831 votes under a cloud of accusations of fraud, didn't get the endorsement he hoped for.

The prime minister told a news conference that the situation at Canada's border with the U.S. is different than the situation for Mexico and said Canada shares the Americans' concerns about security.

"I think we've said repeatedly as a country in our relations with the United States that we share the Americans' concerns for safe and secure borders," the prime minister said. "We believe that is ultimately in all our economic interests, as well. We're prepared to work with the United States on that.

"At the same time," Harper said, "we obviously caution against things that can cause unnecessary barriers, not just to trade but to the ordinary exchange of tourism and social relationships between our countries."

Harper cautioned that Canada is opposed to "things that cause unnecessary barriers to trade and ordinary exchange of tourism."

He said the two leaders spent the day talking about ways to strengthen the North American Free Trade Agreement.

Calderon is also scheduled to meet members of the Canadian Council of Chief Executives, an organization of Canada's business leaders.

The possibility of allowing foreign investment in Mexican oil was raised this week during talks between Canadian and Mexican legislators in Ottawa. The Mexican constitution currently prohibits foreign companies from investing in the oil industry.

The president-elect will meet with Bush on Nov. 9 before heading back to Mexico to prepare for his Dec. 1 inauguration, when he succeeds President Vicente Fox.

His visit to Canada comes a day after Mexico declared at the Organization of American States headquarters in Washington that the proposed barriers along the border won't solve the immigration problem.

Mexico declared it has 27 other countries standing behind it as it slams the American proposal.

Mexican ambassador Alejandro Garcia Moreno says the 28 countries consider the wall to be a unilateral measure that goes against the spirit of understanding.

But neither Canada nor the U.S. have signed the declaration.

Last month, the U.S. Senate approved the bill to build the border fencing along the Mexican border.

Bush signed it into law despite pleas from the Mexican government for a veto.

Bush called it "an important step in our nation's efforts to secure our borders." The bill will also authorize more lighting and checkpoints, and border patrols will be authorized to use new technologies, he noted.

Mexico says it will challenge the fence plans at the United Nations.

With reports from The Canadian Press and The Associated Press