Nigerian migrants who survived a deadly sea crossing last year filed a lawsuit against Italy for violating their rights by supporting Libya’s efforts to return them to North Africa, their lawyers has diclosed.

Seventeen plaintiffs petitioned the European Court of Human Rights last week, Violeta Moreno-Lax, a legal advisor for the Global Legal Action Network, told reporters. She was among four lawyers and several humanitarian groups involved in the case.

The migrants say Italy violated multiple articles of the European Convention on Human Rights, including that people not be subjected to torture, held in slavery, or have their lives put in danger.

The United Nations, rights groups and news organizations say migrants face these conditions in Libya.

This is the first lawsuit to be filed against Italy for its decision to back the Libyan Coast Guard. The country lost a case in the same court in 2012 for directly handing over migrants intercepted at sea to Libyan authorities.

The legal process can take up to three years but should the migrants win they can be awarded damages, and Italy would be forced to abandon its policy of equipping, training and coordinating the Libyan Coast Guard, Moreno-Lax said.

“Using the Libyan Coast Guard as a proxy to turn back migrant boats is just a new way of camouflaging (Italy’s) strategy of fighting irregular migration in the Mediterranean by trapping them in what the Italian Foreign Ministry itself has qualified as ‘the hell’ of Libya,” Moreno-Lax said.

The lawsuit highlights a stand-off between humanitarian groups seeking to save lives on the open seas and Italian authorities backed by the European Union who are trying to stop people from making the dangerous crossing in the first place.

A spokesman for Italy’s Interior Ministry, which has spearheaded the policy, had no immediate comment.

Libyan naval spokesman Ayoub Qassem said the coast guard does its job within the terms agreed with Italy.

“Regarding the abuse and violations against the migrants, these are all considered as individual acts … We can’t say Libyan state institutions commit these acts,” Qassem said.

Italy has supplied Libya with seven refurbished vessels so far, and three more have been promised, while the EU has trained about 190 Libyan coastguards.

Italy is also coordinating communications with the Libyan Coast Guard about possible boats in distress, according to court documents filed recently in Sicily.

Between 2014 and 2017, more than 600,000 migrants arrived on Italian shores, but crossings have fallen dramatically since Italy and Libya signed a memorandum of understanding aimed at stemming the migration flow in February of last year.

During the first five months of this year, arrivals from Libya fell more than 80 percent versus last year to 6,700 during, official data show. Over the same period, the Libyan Coast Guard intercepted almost 6,000 migrants and refugees. In 2017, the Libyans turned back almost 19,000.

Two of the plaintiffs in the lawsuit were intercepted and returned to Libya. They said they were held for two months in a detention center where they were subjected to beatings and extortion, and where even basic food and healthcare was not provided, before returning to Nigeria with the International Organization for Migration.

All the plaintiffs were rescued at sea on Nov. 6 as at least 20 migrants drowned when a part of their rubber boat deflated.

German humanitarian ship Sea Watch 3 rescued 59 people that day and collected the body of a small child, all of whom were brought to Italy.

The Libyan naval vessel, which had been donated by Italy and was operated mainly by a crew trained by the EU, returned 47 to Libya. In a video shot by Sea Watch, the Libyans are seen beating the migrants they intercepted with a rope, and the vessel then speeds off with a man clinging to the side.

Among the survivors returned to Libya, two were subsequently sold to a smuggler and tortured with electricity in an attempt to extort money from their families, said Charles Heller, co-founder of the Forensic Oceanography project, which prepared a report to support the lawsuit.