"A spy network consisting of five members affiliated with the Zionist regime was identified and arrested," said a police intelligence statement quoted by the official news agency IRNA.

The network had been in contact with a middleman from Mossad "with encouragement from the head of a separatist group", it said, without giving further details.

On Wednesday, Iran's intelligence ministry said agents linked to Mossad who were arrested last week were also members of Komalah, a Marxist group which seeks autonomy for Kurdish-populated areas of northern Iran.

They were alleged to have been planning to target "sensitive sites" in the Islamic republic, it said.

Iran and arch-foe Israel have been engaged in a years-long shadow war.

Tehran has accused Israel of sabotage against its nuclear sites and assassinations of key figures, including scientists.