Hossein Alizadeh said he had held the No. 2 post at the embassy in the Finnish capital Helsinki as deputy head of mission. He said he informed the embassy four days ago of his decision to quit after staying off the job for nearly a month.
“I don’t consider myself anymore a diplomat standing beside a brutal Iranian regime,” Mr Alizadeh said, declaring himself a “political dissident”.
Mr Alizadeh said he was considering how to move forward, and so far had not applied for political asylum.
Finland’s Foreign Ministry said it was unaware of Alizadeh’s case.
Mr Alizadeh is the second Iranian diplomat in Europe known to have cast off his job to protest the Iranian government’s policies and crackdown on citizens.
Iranian consular official Mohammed Reza Heydari left his post in Oslo, Norway, in January, and was granted political asylum in that country.