Vienna said Tuesday that it had summoned the Iranian ambassador, on the background of Iran’s sentencing an Austrian for seven-and-a-half years.
The foreign ministry had announced the man’s detention in October and said it is in regular contact with his family.
“He was sentenced to 7.5 years in prison for alleged espionage, with two years of probation being waived in the case of good behavior,” the ministry said.
It found out about the verdict on Monday and summoned the Iranian ambassador on Tuesday to express “our unequivocal protest.”
It added the Austrian ambassador in Iran was able to meet the man during three prison visits since his detention.
“We will continue to exhaust all possibilities to give him and all other imprisoned Austrian citizens all over the world the best possible consular support,” the ministry said.
At least 17 Western passport-holders are detained in Iran, most of them dual nationals, including two Iranian-Austrians.
Tehran insists all have been subject to proper judicial process.
Rights groups and supporters however say they are innocent, and that they are being held as part of a policy of hostage-taking to extract concessions from foreign governments.
Activists fear there may be more cases yet to be confirmed.
An Iranian court on Tuesday sentenced to death an Iranian-German national who supporters say was abducted abroad and forcibly returned to Iran for a show trial.
Germany has condemned the sentence as “inhuman.