Libya migrant boat crisis
Dozens of migrants drown off Tunisia coast after leaving Libya
This was one the deadliest shipwrecks involving migrants trying to reach Europe illegally this year.
Deaths at sea have declined as well, according to the IOM, with 2,833 this year, down more than 38% from 4,581 last year.
Numbers in about 16 centres rose to nearly 20,000, from 5,000-7,000 previously, leading to a worsening of already poor conditions.
The migrants were intercepted near the town of Zliten by one of several coastguard vessels that Italy repaired and delivered to Libya earlier this year.
A new report by the World Economic Forum looks at these patterns of migration and how they affect the world’s cities.
Those trying to cross early on Saturday were intercepted by coastguards from Zawiya, about 45 km west of Tripoli.
Libyan coast guards rescued about 85 migrants off the shore east of Tripoli but about 40 more were believed to be missing, a coast guard officer said.
The LÉ Eithne ship rescued 712 people off the coast of Tripoli as part of an international migrant rescue effort, Ireland’s Defence Forces said.
There are at least 400,000 migrants inside Libya now, many held in detention centres with appalling conditions, writes William Lacy Swing.
The United Nations migration agency said more than 1,000 migrants have been reported dead or missing in the Mediterranean this year.
Many of the boats are believed to have left from the shore around Zuwara and Sabratha in Libya's northwest.
Facebook has apologised after they temporarily took down photos of a shipwreck off the coast of Libya.
An Italian coast guard vessel saved 113 people from a partially-deflated rubber boat.
Boat smugglers often use Tunisia’s proximity to the Italian coast to ship migrants there.