copenhagen — Sweden has summoned the Iranian charge d’affaires to demand the immediate release of Swedish citizens being held in custody in Iran, the Swedish foreign ministry said on Wednesday.

“The Government is working intensively and tirelessly to secure the release without delay of Swedish citizens detained in Iran for no apparent reason,” the ministry said in a statement.

“In late 2023, a man with Swedish and Iranian citizenship was detained for no apparent reason,” the statement said.

A Swedish man in his 20s also was arrested in Iran earlier in January, the ministry said this week.

Those events have added to tense relations between the two countries since 2019, when Sweden arrested a former Iranian official for his part in the mass execution and torture of political prisoners in the 1980s.

Last month, Iran began the trial against a Swedish national, Johan Floderus, a European Union employee who has been imprisoned since April 2022. He was charged with spying for Israel and “corruption on earth,” a crime that carries the death penalty.

The Swedish Foreign Ministry has advised Swedes against traveling to Iran.