Police said in a statement that they had arrested 12 of the suspects, with six still unaccounted for.

The smuggling ring allegedly used small boats with powerful engines to transport between 10 to 30 people at a time from towns on the Tunisian coast to the southern Italian island of Sicily.

Migrants were “subjected to inhumane and degrading treatment” on the journey, lasting around four hours, which put their lives in “serious danger”, police said.

The suspected smugglers are alleged to have demanded payment in cash in Tunisia before departure, with the crossing costing between 3,000 euros and 5,000 euros per person, meaning the alleged traffickers were pocketing between 30,000 euros and 70,000 euros per trip.

The ringleaders were said to be a Tunisian man couple in the Sicilian town of Niscemi – despite them both being under house arrest at the time.

They relied on the help of a series of other people tasked with logistics such as money collection and putting up newly-arrived migrants, including a farmer alleged to have allowed the use of his land as a base for operations.

They now face charges of illegal cross-border trafficking of more than five people, with the aggravating circumstance of inhuman treatment and endangering lives and committing crimes for profit.

While the new Italian government says it will crack down on humanitarian ships that rescue migrants on boats departing from Libya, the majority of migrants arriving in Italy travel from Tunisia.