41 people reportedly died after boat capsized off Italian coast, survivors tell Red Cross

Forty-one people are presumed to have died in a shipwreck close to the Italian island of Lampedusa on Friday, survivors told the deputy general secretary of the Red Cross.

Four migrants told the Red Cross that on Thursday they left Sfax, Tunisia and were shipwrecked the next day during poor weather conditions. The surviving migrants said they had to use life preservers made from inner tubes to stay alive.

The survivors were rescued by the Italian Coast Guard and brought to Lampedusa, the southernmost island of Italy, on Wednesday.

There were 45 people, including three children onboard, the survivors said, according to the Red Cross's Deputy General Secretary Ignazio Schintu.

When the boat sank everyone was together and then were separated, the remaining survivors said, according to the Red Cross.

The survivors told the Red Cross they clung to an abandoned motorless boat they spotted in the distance until their rescue.

Two men, one woman and an unaccompanied 13-year-old are the four people who survived the shipwreck, the International Organization for Migration, UNICEF and the UN Refugee Agency, said in a joint statement.

"Dangerous weather conditions make crossings in iron barges particularly perilous for navigation, highlighting smugglers’ total disregard for the lives of migrants and refugees making these journeys. Only a few days ago, a pregnant mother and a child lost their lives off Lampedusa," the organizations said in their statement.

Thi shipwreck brings the number of people dead and missing in the central Mediterranean, the most active and dangerous migration route in the world, to 1,800, the International Organization of Migration said.

A fishing boat with an estimated 750 people capsized off the coast of Greece in June, considered "one of the most devastating accidents" to happen in the Mediterranean Sea in recent years, according to the International Rescue Committee.

More than 100 people were rescued from that shipwreck and over 80 people died, according to the International Rescue Committee. More than 500 people are estimated to be missing and feared dead, the organization said.

ABC News' Will Gretsky contributed to this report.