The vessel set off with 86 people on board, the International Organization for Migration in Libya said, and women and children were among those who died in the shipwreck.
Greek authorities assumed the victims were asylum seekers because no one was looking for missing people locally. And for more than a month, their identities, and the circumstances of their deaths, remained a mystery.
The prime minister is facing increased pressure from her right-wing coalition partners as the number of migrants trying to enter the country via Lampedusa soars.