United Nations (UN) agencies said at least 112 migrants are believed to have died after an overcrowded smuggling boat capsized off Tunisia last weekend.

The estimate came on Tuesday from the International Organization for Migration (IOM) and the UN High Commissioner for Refugees (UNHCR) for the boat that sank off the Tunisian coastal city of Sfax.

Tunisian authorities initially said 46 people had been confirmed dead but that dozens remained missing.

Spokesman William Spinder of UNHCR said on Tuesday that 52 people have been confirmed dead and “about 60” others are believed dead. He said rescue operations were suspended amid bad weather.

Before the tragedy, UNHCR had estimated that 646 people had died trying to cross the sea to Europe this year.

IOM Spokesman Leonard Doyle said it counted 60 confirmed deaths and 52 people missing and presumed dead from the capsizing off the eastern city of Sfax. Sixty-eight people survived.

Doyle said that the toll makes the capsizing “the single biggest incident of dead and missing this year” on the Mediterranean, after two other shipwrecks off the Libyan coast in January and February that each left 100 people dead or missing and presumed dead.