Libyan coastguard patrol rescued 345 migrants from three boats near Qarabulli on Friday. One hundred others are believed to be drowned after another boat capsized east of the capital.
More than 100 migrants are feared to have drowned off Libya's western coast after their overloaded boat capsized, coastguard officials said on Friday.
The coastguard picked up 16 survivors from the boat just east of the capital, one of whom said the vessel had set off with 120-125 migrants on board, according to a coastguard statement.
Separately, the coastguard said it had brought back to shore more than 300 migrants from at least two other migrant boats east of Tripoli. The issue of migration has surged up the European political agenda in recent years as the numbers fleeing war and poverty jumped.
Libya is one of the main departure points for migrants trying to cross into Europe by sea, usually in flimsy inflatable boats provided by smugglers that often get punctured or break down.
Some make it to international waters where they hope to be picked up by international vessels, but increasing numbers are intercepted by Libya's EU-backed coastguard and returned to Libya.
Departures surged in 2014 when conflict in Libya worsened and more than 650,000 migrants have crossed the central Mediterranean since then. But the traffic has slowed since last July, when smuggling networks on Libya's coast were partially disrupted under heavy Italian pressure.
This year just over 11,400 arrivals from Libya have been registered by Italy's interior ministry, more than 80 percent fewer than during the same period in 2016 and 2017.