Iranian authorities arrested a Swedish-Iranian man in his 60s last year, Stockholm said on January 18, as tensions between the two countries continue to build.
Without identifying the man, Sweden said he had been arrested at the end of November 2023 "without a clear reason" and called for his release. Iran has not yet commented on the issue.
The news comes a day after the Swedish Foreign Ministry summoned the Iranian charge d'affaires and demanded the release of all Swedish prisoners "who are arbitrarily detained."
The unnamed man is the latest Swedish citizen to be arrested by the Islamic republic, which is accused by Western powers and rights groups of detaining foreign nationals to use as bargaining chips.
At least two other Swedish citizens are detained in Iran, including Ahmadreza Djalali, who also holds Iranian citizenship, and Johan Floderus, who worked for the European Union's diplomatic corps.
Djalili, a medical doctor, was arrested in 2016 and was sentenced to death in 2017 for allegedly spying for Israel, a charge he has denied. Floderus, who was detained in April 2022, is accused of the same charge and his trial is ongoing.
Iran is said to be trying to put pressure on Sweden to release Hamid Nouri, a former Iranian prison official who has been sentenced to life in prison for crimes committed during the mass execution of political prisoners in 1988. His appeal was rejected last month.
Iran warned that it "reserves the right to take appropriate measures" after a Swedish court of appeals upheld Nouri's sentence.
Tehran recalled its ambassador from Stockholm after Nouri's initial conviction in 2022. In 2023, it said it would not allow a new Swedish ambassador to enter the country in the wake of a Koran burning row.