An 11-year-old girl, wearing a simple life vest and clinging to a pair of tyre tubes, has been rescued off the Italian island of Lampedusa, telling rescuers she had spent three days at sea after a shipwreck that is feared to have killed more than 40 people.

The girl from Sierra Leone said she had been on a metal boat carrying 45 people and which had set off days earlier from the Tunisian city of Sfax. As the rickety vessel made its way through one of the world’s most dangerous migration routes, it encountered a storm, pitting it against metres-high waves and winds of more than 23 knots.

More than 24,300 people have disappeared or died along the route between northern Africa and Italy and Malta in the past decade.

Even so, the NGOs dedicated to assisting asylum seekers have faced increasing obstacles in their work, including lengthy court battles and escalating intimidation and threats.