Around 500 refugees trying to reach Europe from Africa via the Mediterranean are feared dead after a large fishing boat went down off the Libyan coast last week, according to the United Nations refugee agency and the International Organisation for Migration. The UNHCR confirmed 41 people survived the disaster, some of whom had floated in the sea for days before being rescued. They were taken to Athens on Wednesday.

Survivors’ accounts of what happened differ, but most said they left the Libyan city of Tobruk late last week. Hundreds boarded one large boat, while others got into several smaller boats that were going to make the journey to Europe. The large boat then sank as it was overcrowded. “People died in a matter of minutes,” an Ethiopian survivor told the IOM. “I saw my wife and my two-month-old child die at sea, together with my brother-in-law.”

The incident has again brought up how dangerous the Libya-Italy route is. The 41 survivors will likely not be deported to Turkey, as part of a new plan for asylum-seekers, as the European Union has not yet negotiated an agreement with Libya, The Guardian said. Around 25,000 Libyan refugees have already made their way to Europe in 2016.