At least 17 migrants were found dead and 215 others were rescued aboard a boat drifting off the Libyan coast, the Italian news agency ANSA said late Friday.

The Italian navy vessel “Fenice” had responded to a call for help launched by the migrants on the boat, the agency said.

It remains unclear exactly how the migrants died. Police is questioning the survivors for details, it added.

The UN says at least 3,000 victims lost their lives in 2014 in the Mediterranean, mostly after departing from Libyan shores.

The International Organization for Migration reported that around 1,750 migrants have died in the Mediterranean since the beginning of 2015, a 30-fold increase over the same period last year.

An estimated 60,000 refugees have arrived in Italy in 2015, most of them departing from Libya, according to UN figures.

Anadolu Agency