Libya has recovered 82 bodies washed ashore after a boat packed with migrants capsized near the western town of Zuwara, a Red Crescent official said on Friday.
"About 100 people are still missing," said Ibrahim al-Attoushi, the Red Crescent official, adding that about 198 migrants had been rescued.
The boat sank on Thursday after leaving Zuwara, a major launch pad for smugglers shipping migrants from sub-Saharan Africa or Syria to Italy.
The migrants on board had been from sub-Saharan Africa, Pakistan, Syria, Morocco and Bangladesh, security officials said.
The Italian coast guard, which has been coordinating rescue operations with the European Union off the Libyan coast, could not confirm a sinking.
The Rome-based authority later said some 1,430 people had been rescued in numerous operations near Libya throughout the day on Thursday, and a merchant ship sent to the aid of a wooden boat carrying 125 people recovered two bodies.
Libya's coast guard has very limited capabilities, relying on small inflatables, tug boats and fishing vessels.
Zuwara, Libya's most western town located near the Tunisian border, is a major launchpad for smugglers shipping migrants to Italy.
Libya has turned into a transit route for migrants fleeing conflict and poverty to make it to Europe. Cross-border smuggler networks exploit the country's lawlessness and chaos to bring Syrians into Libya via Egypt or nationals of sub-Saharan countries via Niger, Sudan and Chad.
More than 2,300 people have died this year in attempts to reach Europe by boat, compared with 3,279 during the whole of last year, according to the International Organisation for Migration.
As many as 70 refugees were found dead in a parked lorry in Austria near the Hungarian border on Thursday, and German Chancellor Angela Merkel said the discovery had shaken European leaders discussing the migrant crisis at a Balkans summit.
Libya has been struggling to cope with an influx of migrants, putting them in overcrowded makeshift detention facilities such as schools or military barracks where they live in poor conditions lacking medical care.
The North African country used to deport migrants it caught but with fighting between armed groups having cut off land border crossings to Niger, Algeria and Chad many stay months or years in detention facilities.