The Libyan coastguard said 324 migrants were picked up on Monday trying to leave the North African country on board two rubber boats.
Libya's western coastline is the main departure point for migrants attempting to reach Europe by sea to seek better lives. Most are from sub-Saharan Africa, though recently more Tunisians and Libyans have been trying to cross.
The migrants intercepted about seven miles off the western town of Zuwara on Monday included 35 women and 16 children, coastguard spokesman Ayoub Qassem said in a statement.
They were mostly from four sub-Saharan countries: Chad, Nigeria, Mali, Ivory Coast.
"There are some others from Tunisia, Pakistan and Morocco. There are also 32 persons including eight women and six children from Libya, and three families among them," he said.
The number of migrants crossing from Libya has dropped since July as Libyan factions and authorities - under pressure from Italy and the European Union - began to block departures, especially from the smuggling hub of Sabratha.
But they have continued from the shoreline east of the capital, Tripoli, and dozens are thought to have died after a boat sank off Zuwara earlier this month.
Zuwara was itself a major migrant smuggling hub until 2015, when there was a local backlash against smuggling after a boat thought to be carrying several hundred migrants sank.
So far this year, just over 3,500 migrants have arrived in Italy from Libya, 62 percent fewer than during the same period last year, according to Italian interior ministry statistics.
The top three nationalities declared by migrants arriving in Italy are Eritrean, Tunisian and Pakistani, followed by Nigerian and Libyan.
Reporting by Ahmed Elumami and Aidan Lewis; Editing by Aidan Lewis and John Stonestreet