In the Islamic republic, the crime of espionage can carry the death penalty.
The pair had appeared before a revolutionary court in the Gulf port of Bandar Abbas on April 22, charged with taking pictures of military sites, naval facilities and telecommunication posts on the island of Qeshm.
The Swedish daily Aftonbladet identified the two men as construction workers aged between 30 and 40 from western Sweden.
The Swedish foreign ministry had earlier said its embassy in Tehran was “working intensively” to secure the pair’s release.
Two other Europeans — one French and one German — were jailed by an Iranian court in March after straying into sensitive Gulf waters.
German tourist Donald Klein and French boatman Stephane Lherbier, 32, were each given 18 months by an appeals court for violating Iran’s territorial waters.
Defence lawyers said the pair had strayed into Iranian waters unwittingly while on a fishing trip from the United Arab Emirates last November as they had been using Emirati maps which showed the waters as Emirati.
Three small islands in the Gulf have been disputed by Iran and the UAE ever since the federation won independence from Britain in the early 1970s.
