A plan to increase the number of US troops in Colombia is drawing opposition, not just from left-wing populist leaders in the region but also from moderate governments prompting President Alvaro Uribe to tour the region and try to ease concerns.
Colombia, Washington's main ally in the region, says the deal with Washington is aimed at strengthening anti-drug efforts.
The United States is in talks with Uribe's government about relocating US drug interdiction flight operations to Colombia after being kicked out of neighbouring Ecuador. Colombia expects to sign a deal this month after a final round of talks in Washington.
The plan is expected to increase the number of US troops in Colombia above the current total of less than 300 but not above 800, the maximum permitted under an existing military pact, officials said.
Venezuelan leader Hugo Chavez and allies from Ecuador, Bolivia and Nicaragua accuse the US of setting up a military platform in Colombia from which to attack its neighbours.
But other countries also expressed concern, mainly Brazil and Chile which are seen as serious referents from the region.
I don't like the idea of a US base in the region said Brazilian President Lula da Silva.
Uribe will meet with Lula da Silva, Chile's Michelle Bachelet and other South American leaders starting on Tuesday.
Bachelet called the Colombia-US talks disquieting and said the proposal should be discussed at the August 10 meeting of the South American Unasur group of nations.
The meeting will be held in Ecuador, which has broken off diplomatic relations with Colombia over a 2008 bombing raid targeting Colombian rebels who were camped out on Ecuador's side of the border.
Where was the hysteria when these operations were being run out of Ecuador? said a high-level official in Colombia's Defence ministry who asked that his name not be used.
Mexico is having the worst security crisis in its history due to the drug trade and people are saying we should not help them by doing interdiction operations. It's ridiculous, the official said.