Washington is using satellites to spy on Iran's nuclear sites, Iran's Intelligence Minister Ali Yunesi was quoted as saying on Wednesday. "We believe the United States has been spying against Iran for some time using satellites and other tools," he was quoted as saying on the official IRNA news agency, when asked about U.S. denials that it was using drones over Iran. Yunesi denied allegations by Washington that Tehran was secretly trying to develop nuclear weapons. Iran says its nuclear activities are for generating electricity. "Our nuclear and military activities are transparent. We have nothing to hide," he said. The Washington Post, citing information from unnamed U.S. officials, reported this week that the United States had been flying drones into Iran for the past year looking for evidence of nuclear weapons programmes. The pilotless planes flew into Iran from U.S. military bases in Iraq and used radar, photography and air filters to detect signs of nuclear activity, the newspaper said.