Beppe Caccia, a coordinator for Mediterranea Saving Humans, said the crew of the Alex performed the rescue Thursday after Italian authorities told them to stand down and let the Libyan coast guard handle it.
Groups that operate rescue ships on the Mediterranean Sea say neither the European Union nor the United Nations consider Libya a safe port. Earlier Thursday, the U.N. migration agency reported that a boat from Libya carrying 86 migrants sank late Wednesday and left only three survivors.
The airstrike on a detention center near Tripoli killed at least 44 other migrants a day earlier. Caccia said: "We're happy to have pulled them out of the hell that is Libya."
A Tunisian Red Crescent volunteer says the boat filled with migrants that capsized off the Tunisian coast was carrying more than double its capacity when it sank — 86 people instead of 40.
Of those, 82 migrants remained missing on Thursday, hours after the late Wednesday sinking. Four were saved but one of them died.
Chamseddine Merzoug said in an interview on Thursday via Skype that the rubber boat carrying Africans of various nationalities had taken off from Zuwara, in Libya. He was citing information from the survivors.
He said that "overcapacity of the boat" was the cause of the sinking.
Merzoug said one survivor, from Ivory Coast, was treated in intensive care, "but he died today at 11 a.m."
The U.N. migration agency says a boat carrying 86 migrants from Libya sank in the Mediterranean overnight, and just three people on board survived, with 82 missing.
The shipwreck late Wednesday off the Tunisian city of Zarzis came a day after a deadly airstrike on a Libyan detention center that killed at least 44 migrants.
Tunisian fishermen came across the sinking boat and were able to pull out four men, but could not find any of the other passengers on the boat, said Lorena Lando, head of the International Organization for Migration in Tunisia. One of the four, a man from Ivory Coast, died overnight and the other three remained hospitalized.
Earlier this week, another boat from Libya made it to the Tunisian port of Sfax with 65 people on board.
Migrants who survived the deadly airstrike on a Libyan detention center say they had been conscripted by a local militia to work in an adjacent weapons workshop.
Two migrants told The Associated Press on Thursday that for months they were sent day and night to a workshop inside the Tajoura detention center, which housed hundreds of African migrants.
A young migrant who has been held for nearly two years at Tajoura says "we clean the anti-aircraft guns. I saw a large amount of rockets and missiles too."
The migrants spoke on condition of anonymity for fear of reprisal.
Libya's warring parties are trading accusations for Wednesday's strike, which killed at least 44 migrants.
Aid agencies say even after the strikes, there is no plan for evacuating the facility.