Prime Minister Stephen Harper's firm stance against Cuba's participation in the next Summit of the Americas contributed to an awkward parting of country leaders who failed to produce a joint declaration after a weekend of discussions.

Harper and U.S. President Barack Obama were alone in opposing an agreement that would allow communist Cuban leaders to attend future summits.

Their stance left the Cuban question unresolved as the summit wrapped up Sunday in Cartagena, Colombia.

Colombian President Juan Manuel Santos said it was "unacceptable" that Cuba could not attend the next summit, scheduled to take place three years from now in Panama.

Santos was backed by leaders of other major Latin American countries, including Argentina and Brazil. The presidents of Nicaragua and Ecuador boycotted the summit in solidarity with Cuba.

Harper refused to give in to international pressure, insisting that participating countries must be democracies. He did, however, note that he does not agree with the U.S. embargo on Cuba.

"While we don't support the position of isolating Cuba, we do believe that the summit of the Americas should be restricted to democratic countries, and that Cuba should be encouraged to come as a democratic country in the future...and it's our contention that the Canadian policy is the way to get that kind of result rather than the policy pursued by our American friends," Harper told reporters.

He called it a matter of principle.

"When we take principled positions we're prepared to argue that and discuss them but obviously we don't have our positions dictated either by one country or frankly by any group of countries," he said.

The rift over Cuba and the scandal involving U.S. Secret Service members' alleged dalliances with Colombian prostitutes largely overshadowed Harper's efforts to expand Canada's trade footprint in Latin America.

On Saturday, Harper used his recent budget promise to streamline the environmental review process for new resource projects in Canada as a key sales pitch to investors.

His goal was to also support Canadian business looking for new opportunities in Latin America, but he attended only a few bilateral meetings.

On Sunday, Harper moved on to security issues by touting the Canadian Initiative for Security in Central America, which will offer police and border security training in countries struggling with crime and illegal immigration.

Over the years, Canada has invested millions of dollars in such security training programs.

Violence and drug problems in Mexico and Central America were brought up at the summit, with leaders agreeing to start formal discussions on how to wage the war against cartels and other criminal organizations.

There were also summit forums on indigenous peoples, youth and labour in Cartagena, but Canadian officials did not discuss them with reporters. Diane Ablonczy, Minister of State for Foreign Affairs, did not speak to the media about her participation at the meetings.

With files from The Canadian Press