Mon Dec 21, 1:00 pm ET BOGOTA (Reuters) – Colombia on Monday dismissed Venezuelan President Hugo Chavez's charges that drones flying from Colombia are spying on him, with a senior official saying Venezuelan troops instead may have seen "Father Christmas' sleigh." Chavez, a staunch critic of the United States, said on Sunday the United States was spying on his government with unmanned drones that fly from Colombia as well as the islands off Venezuelan's Caribbean coast. The Venezuelan president called the incursions by the unmanned planes "acts of war" and ordered his air force to shoot them down if they are seen again. "Colombia does not have those capabilities he describes," Defense Minister Gabriel Silva told reporters on Monday. "Perhaps the Venezuelan troops confused Father Christmas' sleigh with a spy plane." Colombia, a close U.S. ally, and OPEC-member Venezuela are locked in a dispute that is hurting bilateral trade ties and raising concerns about possible violence between the Andean neighbors. The dispute intensified over a Colombian agreement to allow U.S. troops more access to its military bases to bolster cooperation against drug traffickers and guerrillas fighting Latin America's longest-running insurgency. Chavez says the base plan is a step toward U.S. aggression against his oil-producing country. The leftist leader has told troops to prepare for possible war and restricted Colombian imports to protest the accord. Tensions further escalated over the weekend when Silva said Colombia is preparing to defend against a possible foreign military attack and Chavez warned Colombia that his country was ready to defend itself against any aggression. The two countries often have sparred when Colombia's long civil conflict spilled across their 1,375-mile (2,200-km) frontier, but the current crisis seems to have heightened risks over a possible flare-up in border violence.