BEIRUT - Lebanese Shi’ite group Hezbollah has detained one of its own operatives who has confessed to spying for Israel, its leader Sayyed Hassan Nasrallah acknowledged for the first time on Thursday, in a case that has shattered the group’s aura of impenetrability. Local media reported the arrest several weeks ago, describing the man as an officer overseeing foreign operations, but Hezbollah had previously declined to comment. Nasrallah told Beirut-based Al Mayadeen TV that the man was detained five months ago and had confessed to working for Israel’s intelligence service, Mossad.