Tesla's CEO Elon Musk and other leading artificial intelligence experts have called on the United Nations for a global ban on the use of killer robots, which includes drones, tanks and machine guns, The Guardian reported on Sunday. "Once this Pandora's box is opened, it will be hard to close," Musk and 115 other specialists from around the globe wrote in a letter. The letter launches an International Joint Conference on Artificial Intelligence in Melbourne on Monday. The experts call autonomous weapons "morally wrong." The report said that the experts hope to add killer robots to the U.N.'s list of banned weapons that include chemical and intentionally blinding laser weapons.