According to an investigative report by Swedish Radio (SR), the couple, Mahdi Ramezani and Fereshteh Sanaeifarid, had applied for and been granted asylum in Sweden by posing as Afghans.
The couple were arrested in April 2021 on suspicion of conspiracy to commit a terrorist crime involving the murder of Jewish figures in Sweden, SR reported.
Due to a lack of evidence, the two were never charged but they were reportedly deported in 2022 for posing a security risk.
"We have strong belief that they were here on a mission on behalf of Iran. They were seen here in Sweden as a very severe security threat. And that's the reason why they were expelled, even if we couldn't prosecute them," deputy chief prosecutor Hans Ihrman told the broadcaster.
While the investigation was classified, SR cited sources saying that the two were working on behalf of the Iranian Islamic Revolutionary Guard Corps, IRGC. The two alleged agents reportedly identified three different targets, gathering addresses and photographs.
One of the suspected targets was believed to be Aron Verständig, Chair of the Official Council of Swedish Jewish communities, who told SR that he had received a call from the Swedish Security Service in 2021, informing him that he was believed to be at risk.
"They basically told me that you have been named as one of the targets of a possible terror crime that involves murder," Verstandig said.
According to SR, the Iranian couple denies the allegations.
Israel accuses Iran of attempting to develop nuclear arms and seeking to counter the Islamic republic's influence in the Middle East. Tehran in turn accuses Israel of being behind a series of sabotages and assassinations targeting its nuclear programme.