Iran shot down an unmanned US spy plane over its Fordu nuclear site, a state-run website reported on Wednesday, a day after it confirmed it was installing a new generation of advanced uranium enrichment centrifuges."An unmanned US spy plane flying over the holy city of Qom near the uranium enrichment Fordu site was shot down by the Revolutionary Guards' air defense units," MP Ali Aghazadeh Dafsari was quoted as saying by the Youth Journalists Club, affiliated to Iran's state TV."The plane ... was trying to collect information about the site's location ," he said, without giving details. He did not say when the incident happened.