ROME: Up to 40 African migrants were feared drowned after their inflatable boat sank near the Libyan coast, survivors told the United Nations refugee agency on Thursday after reaching Italy.

"They said between 35 and 40 people died on Wednesday morning," said Carlotta Sami, the UNHCR spokeswoman for southern Europe. All the dead came from sub-Saharan countries such as Senegal, Mali and Benin.

A team from the Save the Children charity that interviewed some of the survivors said up to 7 children, aged about 15 or 16, were also believed to have died in the incident.

Sami said the boat they were travelling in started to disintegrate shortly after it put to sea from the Tripoli area.

"Unfortunately the rubber was of a very bad quality," she said, speaking by telephone from Sicily, where the survivors had come ashore after being rescued by a German navy vessel.

Save the Children said the German ship brought 283 refugees and migrants to Port Augusta. Two other boats brought a further 669 immigrants to Sicily and southern Italy during the day.

Italy has become one of the main entry points in Europe for immigrants seeking a better life, with more than 85,000 migrants - mostly from Africa and the Middle East - reaching the country so far this year via the Mediterranean.

However, many of the boats are unseaworthy and the United Nations estimates that some 1,900 would-be migrants have died since January trying to make the crossing.