A boat carrying Sudanese refugees caught fire and sank over the weekend off the coast of Libya, killing at least 50 people as it was heading toward Greece, the International Organization for Migration (IOM) said Thursday.

The boat sank on Sunday about 60 kilometers (40 miles) off the eastern Libyan city of Tobruk. Earlier, the IOM said the vessel was carrying 75 Sudanese refugees and only 24 survivors were rescued.

The Libyan Red Crescent said it recovered bodies along the coast about 60 kilometers west and 90 kilometers east of Tobruk, but it is unclear if the bodies were those of the Sudanese migrants. The organization did not provide further details.

In a separate incident, authorities in the western Libyan coastal city of Zuwara rescued 35 migrants, including five women and a child, from a boat off the coast on Tuesday.

Libya has long been a key transit point for migrants fleeing war and poverty in Africa and the Middle East. Earlier this month, a migrant boat capsized off Libya, leaving one dead and 22 missing. In December, at least 61 migrants, including women and children, drowned off western Libya’s coast.

According to IOM’s Missing Migrants Project, at least 434 migrants have died and 611 are missing off Libya in the past eight months. Libya has faced chaos since a NATO-backed uprising in 2011 toppled and killed longtime leader Moammar Gadhafi.