Italy`s Ansa news agency said the suspects were accused of international terrorism association.
The network was allegedly plotting to free its leader, Mullah Krekar, who is already in prison in Norway.
Krekar, born Najm Faraj Ahmad, and two others were arrested in Norway as part of the operation, on suspicion of plotting attacks in Norway and other European countries, according to Italian police.
They face extradition to Italy.
Krekar, the Iraqi Kurdish founder of the radical Islamic group, Ansar al-Islam, has served several jail sentences in recent years, including for praising the killing of staff at the French satirical newspaper Charlie Hebdo.
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