Regional leaders gathered in Bariloche city, in the province of Río Negro, in a move to defuse tensions over the placement of US troops in Colombia, which had sparked a strong reaction from its neighbours. The session wwas broadcasted live, after a request of Colombian President Alvaro Uribe.

Venezuelan President Hugo Chávez said the placement of US bases in Colombia would allow the US military to place soldiers and weapons in the region and increase its sphere of influence. "The US is transporting troops and weapons as it prepares for war," he noted.

Chávez made a detailed analysis on the military policies of the US in the region, in which he claimed Washington would be willing to use its force to secure a daily supply of 20 trillion barrels of oil. Echoing Chávez's words, Bolivian President Evo Morales said "I highly doubt the US would limit itself to Colombia."

Minutes earlier, Uribe backed the Colombian agreement to station US troops in military bases as a tool to fight drug trafficking in the country, the world's largest cocaine producer. Earlier this week, Colombian officials said the deal was done — just awaiting signatures — and Uribe has no intentions of backing down.

"We need to step up efforts to prevent drug trafficking from spreading to other nations of the region," he said today.

"Colombia has reached agreements with the US since 1952. In the nineties we began the Plan Colombia, which is supported by multilateral agreements and resolutions of the UN to fight drug trafficking," Uribe added, detailing previous agreements with other countries of the region that supported the "Plan Colombia" in the past decade.

"Plan Colombia" is a joint initiative between Colombia and the US, originally conceived by Colombian President Andrés Pastrana Arango, between 1998 and 1999 with the goal of ending the armed conflict and creating an anti-drug strategy. The most controversial element of the anti-narcotic strategy is aerial fumigation to eradicate coca.

"The US has provided us with concrete help. Responsibility should go beyond mere discourses," Uribe asserted today, claiming that cooperation with the US has been efficient in the fight against drug trafficking, which he said has meant a heavy burden on Colombia.

Uribe today downplayed the critics of Washington's policies in the region, saying they would respect Bogotá's sovereignty."We should review the concept of joint responsibility. Consumption has massively increased in our region, and we can no longer separate producing from consuming countries...We're all under the threat of the traffickers' empire."

Uribe also blasted the legalization of drug use, less than a week after the Argentine Supreme Court decriminalized the personal use of marijuana in the country. He said those policies helped drug dealers use consumers to carry their drugs.

The decision to stage a summit in Bariloche was announced in Quito earlier this month after Uribe failed to attend a meeting of UNASUR amid increasing controversy over the Colombia-US agreement. After the accord was announced, Venezuelan President Hugo Chávez suggested he might start a conflict with Colombia if the plan came to effect, and said "winds of war are blowing in Latin America."

At the opening of the ceremony today, Ecuadorean President Rafael Correa, the current chairman of UNASUR, supported an open agenda to discuss military agreements and the situation in Honduras, where democratic leftist president Manuel Zelaya was overthrown by a military coup.

"We will seek to adopt tougher measures on Honduras," Correa said. "We need to address our conflict in a democratic manner. There have always been conflicts, but this is the first time that the issue of foreign bases is discussed in a forum."

Correa also asked Uribe to disclose the details of the plan.

The defence budget of the countries in the region has soared in the past two years, growing an average of 30 percent, according to private estimates, boosted by the Venezuelan purchase of Russian Sukhoi fighter planes and tanks, while Brazil has purchased submarine technology and arms from France.

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