Italian officials have held a funeral for 13 migrants who were among up to 800 people who died in a shipwreck in April.

The 13 are the first victims of the shipwreck to be recovered by deep-sea operations being carried out by the Italian navy.

Among those who attended the ceremony on Tuesday in Catania were the mayor of the Sicilian city, Enzo Bianco, and Bouchnafa Ismail, vice president of the Sicilian Islamic Community.

Premier Matteo Renzi has pledged that Italy would do everything possible to try to bring up the bodies. Survivor accounts and undersea examination indicate that hundreds were crammed inside the hold of the smuggler's fishing boat, which capsized when rescuers aboard a nearby container ship approached in waters off Libya on April 18.