Story highlights The Italian coast guard says 8,480 migrants were rescued from Friday to Monday

Save the Children said Tuesday 400 migrants could be missing from a boat

The Italian coast guard cannot confirm that report

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 cannot 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.

Read More