| Latin American nations say there may not be another summit unless the US overcomes its objections to Cuba [AFP]
Argentina's President Cristina Kirchner has stormed out of the Summit of the Americas in protest against a perceived lack of regional support for her country's claims in the dispute with the UK over the Falkland Islands.
The summit in Colombia had already been marred by a lack of consensus among attendees, with Latin America countries opposing the decades-old US isolation of communist Cuba.
Several countries put pressure on Barack Obama to end the ban, as the US president continued to be plagued by a US secret service scandal involving prostitutes.
Al Jazeera's Lucia Newman, reporting from Cartagena, said the summit was at risk of "falling apart" after Kirchner's exit.
"I suppose the collapse shouldn't be too surprising. There was complete disagreement about signing a final statement but the nail in the coffin came when Cristina Kirchner stormed out of the summit followed by Bolivia's Evo Morales.
"[Kirchner] was furious, we are told, because of the lack of full, complete support for Argentina's claim of control of the Falkand Islands," Newman said.
"We understand she was very, very angry that [leaders] didn't even mention the dispute over the islands with the UK."
"She was overheard saying, 'This is pointless. Why did I even come here?'"
Seeking to woo a region whose trade could help create US jobs, Obama has instead had a bruising time at the two-day hemispheric gathering attended by more than 30 heads of state in historic Cartagena.
Brazil and others bashed Obama over monetary expansionism and he has been on the defensive over calls to legalize drugs.
The disagreements came as 16 US security personnel were caught in an embarrassing prostitution scandal at the summit.
Eleven agents from the Secret Service were sent home, and five military servicemen grounded, after trying to take at least one prostitute back to their hotel the day before Obama arrived.
The incident is a major blow to the prestige of the service and turned into an unexpected talking point at the meeting.
For the first time, conservative US-allied nations like Colombia are throwing their weight behind the traditional demand of leftist governments that Cuba be in the next meeting of the Organisation of American States (OAS).
Diplomats said the dispute could block the final declaration planned for Sunday at the closing of the meeting, and originally intended as a hemispheric show of unity.
"The isolation, the embargo, the indifference, looking the other way, have been ineffective," Juan Manuel Santos, the summit host and Colombian president, said of the Cuba issue.
A major US ally in the region who has relied on Washington for financial and military help to fight guerrillas and drug traffickers, Santos has become vocal over Cuba despite his strong ideological differences with Havana.
Al Jazeera's Newman said: "There will not be a final statement, at least one signed by all the nations.
"All the nations, except the US, have insisted there will not be another summit if Cuba is not included.
"This was not the harmonious meeting many had hoped for. There will be no final declaration at the end."
Cuba was kicked out of the OAS a few years after Fidel Castro's 1959 revolution, and has been excluded from its summits due to opposition from the US and Canada.
"All the countries in Latin America and the Caribbean support Cuba and Argentina, yet two countries refuse to discuss it," Eva Morales, Bolivia's president said, referring to widespread support for Argentina's claims to sovereignty over the British-ruled Falkland Islands.
Morales said: "How is it possible that Cuba is not present in the Summit of the Americas? What sort of integration are we talking about if we are excluding Cuba?"
Rafael Correa, Ecuador's president, boycotted the meeting over Cuba, and fellow-leftist Daniel Ortega of Nicaragua also stayed at home.
The leftist ALBA bloc of nations, including Venezuela, Ecuador, Bolivia, Nicaragua and some Caribbean nations, said they will not attend future summits without Cuba's presence.
"It's not a favor anyone would be doing to Cuba. It's a right they've had taken away from them," Ortega said from Managua.
"At this meeting in Cartagena, I think it's time for the US government, all President Obama's advisers, to listen to all the Latin American nations."
Although there were widespread hopes for a rapprochement with Cuba under Obama when he took office, Washington has done little beyond ease some travel restrictions, saying democratic changes must come on the island before any further steps can be taken.
Obama has not spoken of Cuba in Colombia, though he did complain that Cold War-era issues, some dating from before his birth, were hindering perspectives on regional integration.
"Sometimes I feel as if in some of these discussions, or at least the press reports, we're caught in a time warp, going back to the 1950s and gunboat diplomacy and Yankees and the Cold War,and this and that and the other," the 50-year-old Obama said. "That's not the world we live in today."