The man, a Norwegian citizen of Iranian origin, was arrested in Gothenburg on October 21 as part of a joint operation mounted together with the Danish and Norwegian intelligence services.
“This is a case that entails an Iranian intelligence operation in Denmark,” Finn Borch Andersen, head of the Danish Security and Intelligence Service, said at a press conference on Tuesday afternoon.
“In our view, it was an Iranian intelligence agencys plan to assassinate a person who lives in Denmark.”
Borch Andersen said that Danish police had been trying to foil the assassination attempt when they on September 28 made the dramatic decision to close all transport links to and from the Danish island of Zealand, including the Öresund Bridge to Malmö.
“He is charged with establishing an Iranian intelligence operation in Denmark as well as having taken part in the assassination attempt,” Borch Andersen said.
The Danish government reacted swiftly to the revelations, calling home its ambassador in Tehran, and demanding that Iran be punished with new sanctions.
"I have decided to recall Denmark's ambassador in Tehran for consultations… Denmark can in no way accept that people with ties to Iran's intelligence service plot attacks against people in Denmark," Danish Foreign Minister Anders Samuelsen told reporters on Tuesday evening.
The planned operation was "totally unacceptable", he said, adding he was consulting with "partners and allies", including the EU, about possible sanctions.
In a ministry statement issued earlier in the day, Samuelsen said that the Iranian ambassador in Copenhagen had been summoned to the foreign ministry.
“The gravity of the matter is difficult to describe. That has been made crystal clear to the Iranian ambassador in Copenhagen today," he said in a ministry statement.
PET believes that the Iranian agency aimed to assassinate the leader of a Danish branch of the Arab Struggle Movement for the Liberation of Ahvaz (ASMLA), which supports the establishment of a separate Arab state in Irans Khuzestan Province.
The group is classified as a terrorist organization by the Iranian government.
Danish Prime Minister Lars Løkke Rasmussen also promised "further actions against Iran".
“It is totally unacceptable that Iran or any other foreign state plans assassinations on Danish soil. Further actions against Iran will be discussed in the EU," the PM tweeted.
Swedens government has so far made no official comment, with Säpos press release directing the media to PET.