Iran's judiciary confirmed on Sunday the five-year prison sentence given to a Canadian-Iranian member of its nuclear negotiating team on spying charges.
"Mr Abdolrasoul Dorri Esfahani... was among some who were accused of spying and providing information for foreigners and had links with two espionage services," judiciary spokesman Gholamhossein Mohseni Ejeie told reporters.
Some reports have also said Dorri Esfahani has British citizenship.
"The court sentenced him to five years in prison and the verdict is final," Ejeie said.
"He also has a financial corruption case for which a bail has been issued but no indictment has been issued yet."
Dorri Esfahani has a background in the banking sector and was a member of the supervisory board overseeing implementation of the nuclear deal signed between Iran and world powers in 2015.
Since mid-2016, conservative websites and members of parliament have repeatedly accused Dorri Esfahani of spying for Britain.
This was flatly denied by Intelligence Minister Mahmoud Alavi in October 2016, but the case remained open.
The conservative-dominated judiciary has jailed a number of dual nationals and foreigners since the nuclear deal came into force, highlighting the ongoing concern within parts of the establishment over improving ties with the West.
Iran does not recognise dual nationals, which means they cannot receive diplomatic protections such as consular visits.