Researcher Ahmadreza Djalali has been detained since April 2016. He was arrested in Tehran for espionage and 'enmity with God' during a visit for a conference.
An Iranian citizen, the academic has a permanent residence permit in Sweden, where he conducted research in disaster medicine at the prestigious Karolinska Institute, and lived with his wife and two children.
His wife was told of the death sentence on Saturday, as The Local has previously reported, but it was officially confirmed via the Iranian justice system's own news service on Tuesday.
Tehran prosecutors accuse Djalali of passing information about military and nuclear facilities in Iran to Israeli security service Mossad in exchange for money and accommodation in Sweden.
"My husband can't believe this is happening. He is shocked," Djalali's wife Vida Mehrannia told Swedish news agency TT.
Ahmadreza Djalali has been in custody since April last year. Photo: Tomas Oneborg/SvD/TT
Foreign Minister Margot Wallström says that the government will not comment on the allegations, but that the foreign ministry has approached Iranian authorities to protest against the sentence.
A spokesperson confirmed that they had been told by Iranian representatives of the sentence.
"The foreign ministry wants to emphasize that Sweden always condemns the use of the death penalty. We're continuing to work based on the information we have and will immediately bring this up with Iranian representatives, even at a high level," Lina Edimark told TT on Tuesday.
Iran executed at least 567 people last year, according to human rights organization Amnesty International. But the figures are unreliable because Tehran does not keep an official record of all the cases.
In August, Amnesty urged the authorities to release Djalali or give him a fair and secure trial.
"We hope he will be released. He has been in prison since April last year on extremely vague grounds," Amnesty Sweden spokesperson Ami Hedenborg said.
"You have to ask yourself what it is really about. There is a great deal of concern over what may happen," Hedenborg added.