More than 90 refugees are believed to have died after their rickety boat was damaged shortly after leaving the Libyan coast.
Ayoub Gassim, spokesman for the Libyan navy, said on Thursday the coastguard rescued 29 survivors, who said the plastic boat ripped and began filling with water about 42km off the Libyan coast in international waters.
He said a total of 126 refugees were in the boat, mostly African nationals.
The group on board left Tajoura, in western Libya, before dawn on Wednesday morning, and the coastguard received a call for help around 3pm.
The death toll for refugees in the Mediterranean has reached at least 3,800 this year so far, making 2016 the deadliest year ever for refugees and migrants in the Mediterranean. Last year, a total of 3,771 refugees died while trying to reach Europe.
Refugees fleeing war, persecution, and poverty take dangerous trips from Libya to Italy on overcrowded boats, hoping to make their way from there to new lives in Europe.
The rate of drowning has increased as the fragile and often overcrowded boats capsize or sink.
But the high toll comes despite a fall this year in the number of people seeking to cross the Mediterranean to Europe. According to the UN's refugee agency, last year at least one million people made the crossing. This year so far crossings stand at 327,800.
Bad weather, flimsy boats, and the fact that refugees are increasingly taking the hazardous central Mediterranean route from Libya to Italy has lifted the death toll.
A deal between the EU and Turkey largely closed off the eastern route from the Middle East to Europe through Turkey earlier this year.