CAIRO (AP) — The Libyan coast guard says 97 migrants are missing and believed drowned after their Europe-bound boat sank on a perilous crossing of the Mediterranean Sea.

Spokesman Ayoub Gassim says 23 migrants were rescued around 6 miles (10 kilometers) off the coast after authorities received a distress call Thursday morning.

Fifteen women and five children are among those still missing.

He says the boat, which was loaded with African nationals seeking a better life in Europe, "completely collapsed."

Chaotic Libya has become a major avenue of migration, with thousands braving the dangerous sea crossing to Europe. More than 4,500 migrants perished on the crossing in 2016 alone.