The Colombian government has confirmed it has signed a deal to increase the presence of American troops in its territory. A number of South American leaders have expressed deep concerns over the agreement – mindful of previous US ‘meddling’ in the continent.Mexican President Felipe Calderon, after meeting Colombia’s President Alvaro Uribe, dismissed this, however. Calderon said: “Following Mexican principles of foreign policy and the basis of the friendship and close ties we have with the Colombians, we respect the decision any country takes to protect its sovereignty and the security of its citizens.” Colombia says the deal will give US forces access to seven of its military bases to aid its efforts to tackle drug-trafficking and terrorism. Venezuela’s President Hugo Chavez has been one of the plan’s fiercest critics. He says the move is meant to provide cover for an invasion of his country by US forces. Around 600 US military personnel already work in Colombia and advisers have trained thousands of Colombian troops since 2000.