By Candace Piette
BBC News, Bariloche
A scenic region - but will the Bariloche talks turn ugly?
Nestled in the foothills of the Andes, the picturesque Argentine ski resort of Bariloche has plenty to offer visitors.
But the 12 Latin American leaders gathering there for a summit later on Friday will have little time to sample the cool delights of Bariloche in the southern hemisphere winter.
The meeting has been called to discuss a planned accord between Colombia and the US that would allow the American military use of seven Colombian military bases - a deal that has already provoked some heated rhetoric, from, above all, Venezuela's President Hugo Chavez.
For more than a decade, a limited number of US military personnel have been working alongside the Colombian security forces in their fight against drug-traffickers and left-wing rebels, as part of an accord known as Plan Colombia.
The agreement, which has also provided Colombia with millions of dollars in funding and military hardware, has helped to reduce violence and kidnapping and murder rates, according to Colombian President Alvaro Uribe. It has also brought relative safety to Colombia's urban areas.
US support has helped Colombian security forces fight drug trafficking
The latest deal to deploy US aircraft and personnel to Colombian bases comes as Ecuador ends a 10-year agreement allowing the Americans to use its Manta airbase as a regional hub for anti-drug surveillance operations.
For Bogota and Washington, the accord is merely a continuation of their current co-operation.
But it has provoked savage criticism, not only from Mr Chavez, but also Ecuador's President Rafael Correa and President Evo Morales of Bolivia.
Brazil, Argentina, Paraguay, Chile and Uruguay have been more measured but have also expressed their concern about the agreement's impact on the security of the region.
This unease forced Mr Uribe to undertake a week-long regional tour earlier this month to explain the details.
Mr Chavez has described the accord as a "declaration of war", pointing to the short flight times and proximity of the bases to Venezuelan territory.
On Wednesday he increased the pressure, by publicly asking his foreign minister to prepare to break diplomatic relations with Colombia.
"What President Chavez wants is to keep himself in the headlines," says Larry Birns of the Council for Hemispheric Affairs, a Washington-based think tank.
Hugo Chavez says the US-Colombia deal undermines regional peace
"The Colombian bases have given him a chance to take centre stage... Chavez is posturing, he can't do much about Brazilian dominance in the region, but he can try to set the agenda with bluster and threats to Colombia."
And he seems to have done just that.
In Ecuador, Foreign Minister Fander Falconi said on Wednesday that the problems his country had with Colombia would not be resolved with a simple handshake at Bariloche.
In March 2008, Ecuador broke relations with Colombia after troops bombed a Farc rebel camp and pursued guerrilla leaders in Ecuadorean territory.
Colombia's civil conflict and war on drugs have long affected neighbouring Ecuador, where an estimated 130,000 refugees, many from rural areas, are estimated to have fled.
The clampdown on the illegal drugs trade in Colombia has also resulted in cultivation and processing activities spilling over the borders.
Mr Uribe, who has confirmed his attendance at the summit, being held under the auspices of the Union of South American Nations (Unasur), insists that the agreement with the US is a done deal and an internal Colombian affair.
Colombia's Alvaro Uribe is Washington's main ally in the region
"This accord is strategic for Colombia in terms of the policy position that sustains President Uribe," says Facundo Nejamkis, director of the Centre for Political and Economic Studies in Argentina.
"Realistically it would be very difficult for Colombia to take a step back after having talked to so many countries. But at least at Bariloche he can explain the details of what the plan entails and give them some sense of security."
After the Summit of the Americas in April, many countries in the region had expected more sensitivity from President Barack Obama about regional feelings towards US military operations in Latin America, a hangover from the Cold War era.
"The US mishandled the situation, their attitude was, the US wasn't doing anything new in Colombia so why are the Latin Americans complaining about this," says Larry Birns.
Ahead of the Bariloche meeting, the Brazilian defence minister, Nelson Jobim, was sent for consultations to Colombia.
On Wednesday, he announced to the Brazilian media that the Colombians would be giving guarantees at the meeting that their military operations would not overflow into surrounding countries again.
Brazil has a jungle border with Colombia and it too is experiencing the impact of Colombia's military conflict with guerrillas and traffickers moving across.
But stung by the constant criticism from President Chavez, Mr Uribe has said he wants to raise the issue of armament sales in Latin America.
Last month, the Colombian government said anti-tank rocket-launchers found in Farc camps had come from Venezuela, a suggestion that outraged the Venezuelan leader.
Temperatures could be set to rise in Bariloche.