Intelligence Minister Mahmoud Alavi did not say when the arrests took place or which countries the spies allegedly were working for, but indicated that many of the detainees were dual nationals.

"I have repeatedly asked people to inform us if they know any dual national. The intelligence ministry's anti-espionage unit has successfully identified and arrested tens of spies in different governmental bodies," Alavi was quoted as saying by ISNA.

The arrest of dual nationals has increased since Iranian Supreme Leader Ayatollah Ali Khamenei said there had been "infiltration" of Western agents in Iranian decision-making bodies.