The announcement comes after three months of spiraling confrontation with the West that began when new tighter US sanctions took effect at the start of May. Last week Iran captured a British tanker in the Strait of Hormuz after Britain's Royal Marines seized an Iranian tanker off the coast of Gibraltar in July 4.
"The identified spies were employed in sensitive and vital private sector centers in the economic, nuclear, infrastructural, military and cyber areas... where they collected classified information," said a ministry statement read on state television.
It was not immediately clear if the arrests were linked to the case in which Iran said in June it had exposed a large cyber espionage network it alleged was run by the CIA, and that several US spies had been arrested in different countries as a result of this action.