A former Iranian nuclear official who was part of a moderate negotiating team has been charged with spying on Iran's controversial atomic programme, the semi-official Fars news agency reported.
Tehran's judiciary has confirmed that Hossein Moussavian is being held under the auspices of the intelligence ministry at Tehran's notorious Evin prison after his arrest last week.
But this is the first indication that Moussavian, who served under reformist president Mohammad Khatami until 2005 and is also close to ex-president Akbar Hashemi Rafsanjani, has been charged with espionage.
"He is charged with spying on nuclear issues and therefore his case is in the hands of the revolutionary court prosecutors," the agency quoted a source as saying.
"Currently he is in the section of the intelligence ministry in Evin prison (in Tehran) and the investigation is continuing," the source added.
"So far, no decision on the bail has been issued and he is still under arrest."
Hardline Tehran prosecutor Saeed Mortazavi confirmed Saturday that Moussavian was in custody but refused to specify the allegations against him "until the investigations are complete."
Moussavian played a central role in talks that saw Iran strike a deal with Europe under which it suspended its uranium enrichment activities, a halt which was reversed when President Mahmoud Ahmadinejad came to power.
The team under then top national security official Hassan Rowhani was considered close to the centrist Rafsanjani, who was thrashed by Ahmadinejad in 2005 presidential elections.
After Ahmadinejad came to power, Rafsanjani loyalists like Rowhani were removed and replaced with more hardline officials under the new national security chief Ali Larijani, a conservative ex-television boss.
Since leaving the negotiating team, Moussavian has kept a relatively low profile, rarely making comments on the nuclear programme in public although he has urged moderation and flexibility in the nuclear standoff.