Desperate migrants unable to pay for their journeys across the Mediterranean to Europe are being sold to illegal organ traffickers, it has been claimed.

Nuredin Atta Wehabrebi, the first senior figure within a people smuggling operation to become a police informant, told Italian prosecutors he knew of hundreds of men, women and children who had been sold to Egyptian gangs after they failed to come up with the money.

The 32-year-old Eritrean was arrested in Italy in 2014 and sentenced to five years in jail in February for people trafficking. He told Sicilian prosecutors he was now "repentant" over his role in an industry which has seen thousands migrants and refugees killed while trying to cross the Mediterranean into Europe.

He said in a statement: "I was told that those who could not pay were handed to some Egyptians, who killed them to take their organs for resale in Egypt, for the sum of $15,000 (£11,280, €13,450). "The Egyptians arrived with equipment for the extraction of organs and for transporting them in cool bags."

Information provided by Wehabrebi, who is under witness protection, led to the arrest of 23 suspected members of an international criminal network across Italy early on Monday morning (4 July).

The group – detained in Rome, Palermo and Macerata – are alleged to have helped smuggle drugs, arms and migrants from Africa to Europe, and are also suspected of being involved in organ trafficking. Detectives at Palermo's anti-mafia unit, leading the operation, had ordered the arrest of a further 15 suspects.

It is just the latest attempt to break up a people smuggling industry which transported more than a million migrants across the Mediterranean into Europe last year, and which is estimated by Europol to have made $5-6bn for criminal gangs.

Racked with guilt over people trafficking

A raid in June at a perfume shop in Rome's city centre saw more than €500,000 seized from the alleged finance centre of one trafficking cell, as well as data on financial accounts and names of foreign citizens. The gang responsible was alleged to have sold fake family reunification documents to help migrants reach Europe, charging $10-15,000 a time.

Wehabrebi said he was racked with guilt over his part in the people trafficking industry and wanted to help bring his former gang members to justice. Thousands flee his home country of Eritrea each month to escape poverty and the repressive ruling government.

"There have been too many deaths in the sea," he said in a statement to Sicilian prosecutors. "People only know about a minimal number of them. Eight in 10 Eritrean families have lost someone on the boats."