A group of survivors from a sinking migrant rubber dinghy have accused Italy of violating their human rights by "subcontracting" their rescue to Libya.
The 17 Nigerian migrants claim they were subjected to slavery, torture and other degrading and inhuman treatment when they arrived in Libya after being rescued.
They are accusing Italy in the European Court of Human Rights over the 2017 deal in which Libya agreed to help reduce the number of asylum-seekers reaching Europe.
The deal involved using EU funds to train and equip the Libyan coast guard to patrol its coasts and bring migrants back to Africa.
The policy apparently worked: Only 6,731 migrants have arrived in Italy so far from Libya in 2018, 84% down from 2017 and 78% down from the year before, according to interior ministry figures.
But the migrants, backed by human rights groups, say the deal means Italy is flouting its international responsibility to rescue migrants at sea and bring them to safety.
They claim Italy is responsible because it maintained "effective control" over the Libyan rescuers via its own coast guard coordination center in Rome and an Italian Navy vessel docked off Tripoli that coordinates rescues locally.
The case concerns a dinghy carrying 130 mostly Nigerian immigrants that sank off the coast of Libya on November 2017. It is estimated 20 people died.
The Libyan coast guard, aboard the Italian-provided Ras Jadir vessel, was first on the scene, but German aid group Sea Watch 3 also responded with dinghies and rescued some 59 people.
Many of the migrants made desperate attempts to reach the European boat for fear the Libyan coast guard would take them back to Africa.
Two of the 17 Nigerians who filed the case were rescued by the coast guard and brought back to Libya, where they reported being tortured and suffering other rights violations.
Human rights lawyer Loredana Leo said they are now back in Nigeria, having agreed to return to escape the Libyan detention centres. A group of lawyers representing the migrants are asking for the court to reward "moral reparations" to their clients, though they said it would likely be two to three years before a decision is reached.
Italy has defended its migrant policy, claiming it has saved lives and slowed the number of migrants who risk their lives paying Libyan-based smugglers to ferry them to Europe aboard flimsy dinghies.