By Agence France-Presse
"These young people have already suffered enough violence and abuse during their journey to Italy and are particularly vulnerable," Raffaela Milano, the director of the Italian arm of Save the Children, said in a statement.
She called for an "immediate" response to the call by Catania prosecutors to allow the minors on board the Dutch-flagged rescue ship Sea Watch 3, currently sheltering from bad weather off Sicily, to be disembarked.
The United Nations refugee agency (UNHCR), its children's agency (UNICEF) and the International Organization for Migration (IOM) also called for an "urgent" solution for the minors and other migrants, saying the situation was "critical".
But far-right Interior Minister Matteo Salvini repeated his refusal to take in the migrants, and claimed the 13 unaccompanied minors were nearly 18 years old and not children.
"I will not change my mind. Italy's ports are closed and will remain closed to people traffickers and their accomplices," he said.
Salvini has insisted Germany or the Netherlands take responsibility for the 47 mainly sub-Saharan African migrants, who were rescued off Libya by the German NGO Sea Watch a week ago.
"Dutch ship and German NGO? Amsterdam or Berlin are waiting for you," he said.
Dutch Migration Minister Mark Harbers said his country "was not obligated" to find a solution, telling Italy's Corriere della Sera daily that the Sea Watch 3 had acted "of its own initiative".
"It is up to the captain to find a safe port for the 47 migrants he saved," he said in the interview, adding that the Dutch government would "not participate in an ad hoc solution".
'Every minute counts'
"For three days we have faced storms, strong winds and heavy rain," a doctor on board told ANSA news agency.
The migrants "are wet because there is not enough room under cover. They have no room to rest," she said, adding that many of them had scars from violence inflicted on them in Libya.
The mayor of Syracuse, Francesco Italia, has said he would welcome those rescued and some inhabitants in the Sicilian coastal city on Saturday hung white sheets from their balconies, with the message "let them disembark".
Dozens of residents gathered for a sit-in on the beach, where the ship could be seen just over a mile out.
Sea Watch called for "an end to this odyssey" and cited a 16-year-old Guinean onboard who left home two years ago to find work to support his family after his father died, and who said he was forced in Libya to work at gunpoint for no pay.
"They killed one of my friends in front of me. He was killed because one morning he couldn't get up to go to work," he said.
Milano warned that "every extra minute spent on the ship... is likely to leave indelible marks that these youngsters will carry with them for the rest of their lives".
Migrants rescued by ships have frequently been left in limbo since Italy's anti-immigration government began turning them away last summer.
Since coming to power last year, Italy has been demanding greater solidarity from reluctant fellow EU states.
But EU members have failed to agree on a permanent mechanism to relocate migrants who reach Europe's shores, even though arrivals have dropped sharply since a peak more than three years ago.