South American leaders have issued a statement warning "foreign military forces" not to threaten the sovereignty of any of the region's nations.

The declaration, which was signed by all 12 leaders of the Union of South American Nations (Unasur), came after a lengthy debate on Friday on plans to increase the presence of US troops at bases in Colombia.

The statement "reaffimed that the presence of foreign military forces must not ... menace the sovereignty and integrity of a South American country and in consequence regional peace and stability".

It deliberately avoided specific mention of the US military in order to allow all the leaders, including Alvaro Uribe, the Colombian president, to sign the text.

Regional fears

The extraordinary meeting the Argentine mountain resort of Bariloche was called after Venezuela, along with Bolivia and Ecuador, complained that the US military could use seven bases in Colombia as launch points to overthrow their governments.

"The US global strategy for domination explains the installation of these bases in Colombia," Chavez said, holding up a document he said set out the US air force strategy to achieve that aim.

An attempt by Evo Morales, the Bolivian president, to get other leaders to sign a declaration rejecting the US deal with Colombia was rejected.

"As long as there are uniformed foreigners in a South American country, it's difficult for us to think there can be peace," he had told the summit.

Colombia has insisted that the US troops are vital to tackle drug trafficking in the region and pose no threat to its neighbours.

Uribe told the summit on Friday that he would "not cede one millimetre of sovereignty" under the deal.

"We are not talking about a political game, we are talking about a threat that has spilled blood in Colombian society."

US expansion

But Eva Golinger, a consultant to the Venezuelan government, told Al Jazeera that the US military deployment was not necessary.

"It has been made clear in other US documents this year, particularly one on irregular warfare, about the need not to have permanent troops stationed in any one country but to have this type of mobility which allows for effective non-conventional military operations - so that's the fear," she said.

"The fear comes in the form of territorial occupation of US military forces or an access to the entire infrastrucure of Colombia for an alleged war against drugs and that doesn't pan out."

Under the plan, about 300 US troops are already stationed in the country, but the new agreement allows the expansion of the force to 800 US soldiers and 600 civilian officials.

Many Latin American nations are wary of US intervention in the region, recalling Washington's backing of right-wing military governments in the past.

Brazil, Chile and Argentina have demanded binding guarantees be made that the US military assets and personnel in Colombia not be used for any other purpose other than their stated mission of fighting drug-traffickers and Colombian rebels.