Iranian authorities have sentenced a member of the country's nuclear negotiating team to five years in jail, Tasnim news agency reports.
Wednesday's report did not identify the person sentenced, but said a Tehran appeals court had confirmed the sentence.
Reports last year in Iranian media said a nuclear negotiator with dual nationality was arrested after being accused of providing sensitive economic information to Iran's enemies.
The only member of the nuclear negotiation team known to be facing criminal charges is a dual Iranian-Canadian national named Abdolrasoul Dorri Esfahani.
Canadian officials did not immediately respond to a request for comment.
In August 2016, hardline news outlets said authorities detained Esfahani, who reportedly focused on lifting economic sanctions as part of the atomic accord.
Separately a senior EU diplomat said European countries will do their utmost to preserve a deal limiting Iran's nuclear program despite misgivings by US President Donald Trump.
"This is not a bilateral agreement, it's a multilateral agreement. As Europeans, we will do everything to make sure it stays," Helga Schmid, secretary general of the EU's foreign policy service, told an Iranian investment conference in Zurich.
The deal was brokered in 2015 by the bloc between Iran, the United States, France, Germany, Britain, Russia and China.
Trump is weighing whether the pact serves US security interests as he faces an October 15 deadline for certifying that Iran is complying, a decision that could sink an agreement strongly supported by the other world powers that negotiated it.
Schmid said Europe has concerns about Iran's role in regional affairs, but that those issues were not part of the nuclear accord known as the Joint Comprehensive Plan of Action.
