Rome ( CNN ) Italy is coping with a rising wave of desperate migrants from Africa and Middle East hoping to make it to Europe . From Friday to Monday , a total of 8,480 migrants were rescued , according to the Italian coast guard , which said it received on Monday -- alone -- SOS calls from 20 boats in distress . On Tuesday , a spokesman with Save the Children told CNN the group fears 400 migrants could be missing , citing testimony from survivors who said their ship carrying 550 people capsized in the Mediterranean Sea about 80 miles off the Libyan coast . The Italian coast guard , however , told CNN that while it is taking the report seriously , it can not confirm such an incident and has not yet found evidence at sea to indicate a migrant boat carrying approximately 550 has capsized with 145 rescued . An operation that included boats and planes did not find any survivors , nor bodies , nor any evidence to indicate a particular boat capsized , Coast Guard official Filippo Marini said . There has been a recent upsurge in migrant boats crossing the Mediterranean into Italy and an increase in rescues performed by the Italian Coast Guard to aid migrant boats . Why migrants are dying trying to reach Italy . According to the International Organization for Migration , Italy registered more than 10,000 migrants arriving in the first three months of 2015 , and about 2,000 were rescued at sea during the first weekend of April in the Channel of Sicily . Most migrants recorded this year come from countries in West Africa as well as Somalia and Syria , the IOM said . They use Libya as a country of transit . At least 480 migrants have died while crossing the Mediterranean since the beginning of the year , often because of bad weather and overcrowded vessels used by smugglers , the IOM said . Sometimes the captains and crews abandon the ships , leaving passengers to fend for themselves . Last week : 978 migrants rescued in one day in Mediterranean Sea . CNN 's Ralph Ellis contributed to this report .
The Italian coast guard says 8,480 migrants were rescued from Friday to Monday . A total of 1,995 people died in the Mediterranean Sea during that time period -- a record for one day and an increase on last year's total.