Tunisia on Wednesday announced the sacking of officials accused of negligence over a shipwreck this weekend that killed at least 66 migrants.
Tunisian authorities, which on Sunday said they had recovered 48 bodies, provided no new figures but said the coast guard was still searching for dozens of missing migrants.
Ministry spokesman Khalifa Chibani earlier on Tuesday said the dead identified so far were "36 Tunisians and 12 foreigners", referring to migrants from sub-Saharan Africa.
But on Tuesday, IOM said crews were still conducting search and rescue operations with the help of military aircraft and divers, "in the hope of rescuing survivors and recovering the bodies of the victims".
On Monday, the premier had called for greater efforts to quickly dismantle the "criminal networks that profit from these young people looking to emigrate and putting their lives in danger".
The International Organisation for Migration (IOM) said that the boat was overloaded and went down near the southern island of Kerkenna. They were being transported on board a vessel that could not hold more than 80 people.
There are 851 refugees and 109 asylum-seekers registered with UNHCR in Tunisia.
Tunisia stopped about 6,000 migrants leaving its coast for Europe in the first five months of the year - a sharp increase from the few hundred prevented in the same period last year, an interior ministry official has disclosed.
Salvini used the trip on Sunday to promote his anti-immigration stance, saying he would not allow Italy to become "the refugee camp" of Europe.
As in other North African countries, desperate youth and even entire families are known to set off from Tunisia to attempt the risky Mediterranean crossing.
Tunisia's navy scoured choppy waters Monday for survivors and victims of the Mediterranean's worst shipwreck in months, with the United Nations migration agency warning more than 100 people may have been killed.