Italy let minors and sick people off a German-flagged rescue vessel Sunday but refused to let 35 male adult migrants off, to the rejected survivors' despair.
Interior Minister Matteo Piantedosi earlier said those who do not "qualify" would have to "leave territorial waters", as three other humanitarian vessels pleaded with Rome for a safe port.
The Ocean Viking, Geo Barents and Rise Above are carrying 900 migrants between them.
Three female minors and a baby were the first off the Humanity 1 in Catania port in the early hours, followed by male minors, SOS Humanity's press officer Petra Krischok told AFP.
After that, male adults with medical issues were allowed off. In all, 144 people disembarked.
"Thirty-five male adults are still on board. For now, we stay here and wait," she said.
"The mood among the survivors is extremely depressed. One person just suffered a breakdown," she added.
The Humanity 1 had been requested by Italian authorities to come to the Sicilian harbour, but not assigned a safe port. It was not immediately clear whether it would be ordered to leave.
- 'Treated as objects' -
Italy's new far-right government, which was sworn in last month, has vowed to crack down on boat migrants coming from North Africa to Europe.
Opposition member of parliament Aboubakar Soumahoro, who was present as those chosen were disembarked, slammed the "selection of shipwrecked migrants", which he said broke international law.
He said far-right Prime Minister Giorgia Meloni's government was treating "the worn-out bodies of shipwrecked people, already exhausted by cold, fatigue, trauma and torture... as objects".
"If the remaining castaways are rejected... we will challenge this decision in all appropriate institutions", he said on Twitter.
Piantedosi said Saturday those migrants not allowed to disembark would have to be "taken care of by the flag state" -- a reference to the national flags under which the vessels sail.
Two of the charity boats -- the Humanity 1 and Mission Lifeline charity's Rise Above -- sail under the German flag.
The other two -- SOS Mediterranee's Ocean Viking and Doctors Without Borders' Geo Barents -- are registered in Norway.
The Norwegian foreign ministry said Thursday it bore "no responsibility" for those rescued by private Norwegian-flagged ships in the Mediterranean.
Germany insisted in a diplomatic "note" to Italy that the charities were "making an important contribution to saving human lives" and asked Rome "to help them as soon as possible".