Hugo Chavez accused the Netherlands on Thursday of allowing the United States to use Dutch islands off Venezuela's Caribbean coast to prepare a possible military attack against his country. The Venezuelan leader said the US military, to prepare for a possible offensive, has sent intelligence agents, war ships and spy planes to Aruba, Curacao and Bonaire, which are self-governing Dutch islands. "They are three islands in Venezuela's territorial waters, but they are still under an imperial regime: the Netherlands," Chavez said during a speech at a climate change conference in Denmark. "Europe should know that the North American empire is filling these islands with weapons, assassins, American intelligence units, and spy planes and war ships." In Washington, State Department spokesman Ian Kelly denied that US military personnel in the Caribbean are planning to attack Venezuela. "These allegations are baseless. These are routine exercises. We seek cooperation with the region," Kelly said. Chavez did not offer evidence supporting his accusations, but he blamed the Netherlands and said the European Union should take a stance. "I would like to know that the European Union has to say about this," Chavez said. "The Netherlands is responsible for this." Chavez claims it is part of a broader plan by Washington to undermine leftist governments throughout Latin America and the Caribbean, including Ecuador, Nicaragua, Bolivia and Cuba. "It's a threat to all the people of Latin America and the Caribbean," he said in a speech on the sidelines of the climate change conference in Denmark The socialist leader has repeatedly accused President Barack Obama's administration of conspiring with neighboring Colombia to topple his government. Chavez's latest remarks were his strongest yet directed at the Netherlands. Three years ago he also bickered with the Dutch government, calling its defense minister a "pawn of Washington" who was part of an orchestrated campaign to vilify him as a "tyrant making plans for invasions of neighboring countries." Venezuela and Colombia have been feuding for months over an agreement between BogotÃ¡ and Washington allowing the US military to increase its presence at Colombian bases through a 10-year lease agreement. American troops also are stationed at airports in Aruba and Curacao. "Venezuela is being surrounded by military bases," Chavez said. Colombian and US officials have dismissed Chavez's concerns that Colombian bases could be used as launching pads to try to unseat him, saying their sole objective to fight drug trafficking and leftist guerrillas within Colombia. Chavez also took aim at Obama during Thursday's speech, saying the US president did not deserve the Nobel Peace Prize because he is continuing warlike policies. "Obama should give back the prize," Chavez said, suggesting that his close ally - Bolivian President Evo Morales - would have been a better choice.