Italy has begun raising the wreck of a fishing boat that sank in April 2015, drowning hundreds of migrants packed on board, its navy said.

The disaster is feared to have killed up to 800 people, making it one of the deadliest shipwrecks in decades of seaborne migration from North Africa towards Europe.

The navy has recovered 118 bodies, but hundreds of corpses are believed to be trapped below deck, where survivors said migrants including many women and children were locked.

Many of the recovered corpses were buried in Malta. 

Navy video footage showed a large yellow frame-like apparatus attached to a ship being lowered into the water to a depth of about 370 metres (1,200 feet), where it gripped on to the wreck. Recovery coordinators applauded from their control room as the raising began.

The hulk will now be placed in a 30-metre-long refrigerated structure while emergency services start recovering bodies from inside. Experts will examine and try to identify the victims.

The vessel sank about 135 km (85 miles) north of Libya, from where it departed, and will be taken to the port of Augusta in eastern Sicily.

Public outrage at the disaster, in which only 28 people are known to have survived, prompted the European Union to restore rescue operations in the Mediterranean.

The recovery of the boat is taking place while thousands more migrants are rescued from the Mediterranean every week.

Moas reported this morning that it found a boat packed with some 500 migrants off the Libyan coast.