Italy's new far-right government has prevented 35 men from leaving a migrant ship which has been requesting access to an Italian port for two weeks.
Minors and people with medical issues were allowed to disembark in Sicily. The Humanity 1 was one of four vessels carrying migrants waiting for permission to dock in Italy.
The new Italian Prime Minister, Giorgia Meloni, has promised to crack down on migrants travelling across the Mediterranean from North Africa.
Italy is one of the main entry points into Europe and since the start of the year 85,000 migrants have arrived on boats, according to the UN.
Many of the migrants set sail in small boats and are rescued by charity vessels during their journey.
In total 144 people were allowed to disembark the Humanity 1, which sails under a German flag, on Sunday morning.
Italian Interior Minister Matteo Piantedosi said those who did not "qualify" as vulnerable would have to leave Italian waters and should be taken care of by the "flag state".
The charity which owns the ship said the mood among the migrants is extremely depressed: "One person just suffered a breakdown," Petra Krischok of SOS Humanity told the AFP news agency.
Preventing people who need help from disembarking goes against international law, the charity says.
Three other ships carrying around 900 people have also requested access to an Italian port but so far have not been allowed to dock.
Italy's new prime minister put the issue of migration at the centre of her government in her maiden speech to MPs.
"We must stop illegal departures and human trafficking," Ms Meloni said, but stressed that she does not intend "to question the right of asylum for those fleeing wars and persecutions".
In a recent interview she also said responsibility for the migrants on board lies with the country where the ship is registered, otherwise it becomes a "pirate ship".
Ms Meloni leads the Brothers of Italy party, which has its roots in Italian post-war fascism, and has come to power at the head of a coalition which includes the far-right League and Silvio Berlusconi's right-of-centre Forza Italia.