Officers arrested 13 Italian, Tunisian and Moroccan suspects in a dawn raid on the network accused of trafficking people and contraband cigarettes, a police spokesman told AFP.
The traffickers brought migrants from Nabeul in north-eastern Tunisia to Trapani on the west coast of Sicily, police said in a separate statement.
The gang would bring between ten and 15 people a time, earning up to €70,000 per four-hour crossing, with hundreds of kilos of contraband cigarettes also stashed in the boats.
The police statement said that "some members" of the network had jihadist sympathies, showing "hostile attitudes to Western culture" and "spreading propaganda via fake profiles on social media".
In a wiretapped telephone conversation, one of the gang's associates asked fellow members to pray for him while he went to France to carry "dangerous actions, after which he might not be able to return".
Since the summer of 2017, Italy has seen a rise in Tunisian migrants arriving in Sicily or on the island of Lampedusa, despite a repatriation agreement with the Tunisian government.
The Italian Interior Ministry says 6,000 Tunisians landed in 2017 and more than 1,300 have arrived since the start of this year.
That number, however, does not include the so-called "ghost landings", of which the only trace is wet clothes found on the beaches of western Sicily.