So far this year, some 29,000 migrants, a lot of them fleeing poverty in sub-Saharan Africa, have arrived in Italy after being rescued by European military ships or private charity organizations.
But aid groups say another timetable might be behind a weekend spike: the start of beefed-up Libyan coast guard patrols created to prevent migrants from reaching Europe, the Associated Press said.
International Organisation for Migration spokesman Leonard Doyle said that better spring weather had encouraged smugglers to take migrants out of detention centres in Libya.
Between Friday and Sunday, more than 8,500 migrants arrived at Sicily's ports following a total of 55 rescue operations, which also recovered 13 bodies.
Italy and Libya inked a deal in February calling for Italy to train Libyan coast guard officers and to provide them with a dozen ships to patrol the country's lawless coasts, it added.
The International Organization of Migration have recorded 913 migrant deaths so far this year in the Mediterranean.
"This was an overwhelming search and rescue activity by all sides involved", UNHCR spokesman Babar Baloch said.
The majority of these migrants are originally from Nigeria and Senegal and they were held captive in detention camps in Libya by rogue groups who treated them horribly and traded them as slaves.
Their numbers are expected to rise with spring's good weather.
The entry into force of the new Libyan patrols could heighten tensions that have already flared between the European Union and humanitarian organizations, which have assumed increasing role in rescuing migrants as their vessels tend to patrol closer to Libya's territorial waters, and their numbers have skyrocketed in the last two years.
Last year, the estimated death toll among migrants and refugees on the Mediterranean was at least 5,000 - a new annual record, according to United Nations agencies.
"The smugglers have clearly taken them to sea and pushed them out in the hope and belief that they would be rescued". In 2015, more than one million people crossed the sea - mostly from Turkey to Greece - with 3,771 deaths recorded.