Hugo Chavez celebrated Venezuela's Army day showing offsome of his country's military power. His new big project is unmanned aircraft, and Iran is helping to design and build them. The Government claims that the drones will be used exclusively for defense and to monitor pipelines, dams and other rural infrastructure. But not everyone is convinced. The Iran-Venezuela alliance has Washington worried that both countries could team up to build more sophisticated weapons to attack the US. Al Jazeera's Teresa Bo reports from Caracas.