Floderus was arrested at a time when an Iranian national was being tried in Sweden
Floderus was arrested at a time when an Iranian national was being tried in Sweden AFP

Iranian authorities have accused a Swedish EU diplomat, held in a Tehran prison for more than 600 days, of conspiring with Iran's arch-enemy Israel, the judiciary said Sunday.

"Johan Floderus is accused of extensive measures against the security of the country, extensive intelligence cooperation with the Zionist regime and corruption on earth," the judiciary's Mizan Online news agency said.

Corruption on earth is one of Iran's most serious offences and carries a maximum penalty of death.

Floderus, 33, was arrested on April 17, 2022, at Tehran airport as he was returning to Iran from a trip with friends.

The Swede, who works for the European Union diplomatic service, is being held in Tehran's Evin prison.

His arrest came while an Iranian national, Hamid Noury, was being tried in Sweden over the mass executions of dissidents in Tehran in 1988 -- ultimately receiving a life sentence in July 2022.

The Court of Appeals in Sweden is expected to announce a verdict in the case on December 19.

Mizan published photos of a handcuffed Floderus, who is being held in Tehran's Evin Prison, appearing before judges in a pale blue prison uniform as the charges were read.

The prosecution claimed Floderus had gathered information on Iran's "nuclear and enrichment programmes", carried out "subversive projects" for the benefit of Israel and established a network of "agents of the Swedish intelligence service".

It further claimed he was involved in "intelligence cooperation and communication with the European Union" and exiled opposition group, the People's Mujahedin (MEK), according to Mizan.

The next date of the trial was not yet known.

EU's top foreign policy chief Josep Borrell called Sunday for his immediate release, saying "there are absolutely no grounds for keeping Johan Floderus in detention."

Sweden's Foreign Minister Tobias Billstrom added: "There is no basis whatsoever for keeping Johan Floderus in detention, let alone bringing him to trial."

Tehran-Stockholm ties soured after the execution in May of Iranian-Swedish dissident Habib Chaab, convicted of "corruption on earth" after being vanished during a visit to Turkey in 2020.

Academic Ahmadreza Djalali, another Iranian-Swede, was arrested in Iran in 2016 and sentenced to death on espionage charges. He remains under threat of execution.

Several other Europeans are detained in Iran, including four French citizens.

One of them, Louis Arnaud, was sentenced in November to five years in prison for propaganda and endangering the security of the Iranian state.

Iran's relations with the EU improved after a nuclear deal in 2015 that lifted sanctions and looked set to boost trade.

But they have worsened considerably since the US effectively scrapped the deal in 2018.

The EU has imposed new sanctions on Iran after accusing it of providing Russia with drones for use in the Ukraine war, which Tehran denies.

It also sanctioned Iran over its response to nationwide protests last year triggered by the death in custody of Mahsa Amini, a young Iranian-Kurdish woman arrested in September 2022 for allegedly violating the Islamic Republic's strict dress code for women.