Iran's elite Revolutionary Guards is saying its forces have shot down an Israeli drone as it approached an Iranian nuclear site. The Guards issued a statement saying forces fired a missile at the drone as it neared its uranium enrichment facility in Natanz, more than 185 miles south of Tehran. The statement did not say when it shot down the drone, nor did it elaborate on how the Guards knew the drone was from Israel. Israeli officials could not be immediately reached for comment. Israel has not ruled out taking military action against Iran's nuclear facilities if its capability to build an atomic weapon progresses. (More Israel stories.)