Dozens of migrants are feared dead after an 11-year-old girl was found alive in the sea off Italy, a rescue group said.

More than 40 migrants are feared dead near Lampedusa in Italy after an 11-year-old lone survivor said the boat he was on capsized, a rescue team said on Wednesday.

“We think he was the only survivor of the shipwreck and that 44 other people drowned,” said the Compass Collective, which helps rescue migrants in the Mediterranean.

The group’s ship Trotamar III “heard calls in the dark” of the girl on Wednesday morning at around 2:20 am (0120 GMT) while on its way to another emergency.

“The 11-year-old girl, originally from Sierra Leone, was floating in the water for three days with two improvised life jackets made from inflated tire tubes and a life jacket,” the group said in a statement. Compass Collective also released photos of the tire tubes and rescuers treating the girl.

Mauro Marino, the doctor who examined her, told the Repubblica daily that he believed the girl had been at sea for about 12 hours.

The girl told rescuers that the iron boat left Sfax, Tunisia. He said the boat sank within seconds when strong storms hit with waves of 11 meters and that he – and two others – were together in the water for a while but lost contact, the BBC reported.

“The girl had no water to drink or food and was hypothermic, but she is active and determined,” Compass Collective said.

A spokesperson for Mediterranean Hope, another charity, told AFP that the girl was recovering in hospital after being rescued.

Deputies found the girl “extremely tired,” spokeswoman Marta Bernardini said.

The Italian news agency, ANSA, reported that the coast guard and police boats were searching the area where the shipwreck was found.

“They have not found the bodies or any traces of clothing,” ANSA wrote.

According to the International Organization for Migration, more than 30,00 immigrants have died or are still missing while trying to cross the Mediterranean Sea since it started recording statistics 10 years ago. The BBC reports that Italy has struggled, receiving more than 63,000 this year alone, according to data released by the United Nations.

Last year, at least 64 peopleincluding eight children, died when their overcrowded wooden boat ran aground a few hundred meters off Italy’s Calabrian coast and broke up in rough seas.