ROME (AP) — Aid groups have revised to at least 170 the number of suspected dead from a weekend migrant shipwreck off Libya.

The International Organization of Migration and U.N. refugee agency increased the estimate from around 110 after interviewing the four survivors of the shipwreck who arrived in Trapani, Sicily, on Monday aboard the Norwegian rescue ship Siem Pilot.

IOM spokesman Flavio Di Giacomo said the survivors included three men and one woman from Ethiopia and Eritrea. They reported having set off from Libya aboard a wooden boat that started taking on water and sank after the engine broke.

The survivors said about 170 people were missing, and that they were in the sea for hours before being rescued Saturday.

The survivors, suffering from shock and exhaustion, have been hospitalized.