About 1,000 North African migrants on a dozen boats have reached the Italian island of Lampedusa overnight.
Others have been sighted approaching the island, off the coast of Tunisia. Most of the migrants are said to come from Tunisia amid turmoil there and in neighbouring Libya.
Several thousands have arrived on the Sicilian island since mid-February.
Italy has sought EU help as it copes with the influx amid fears of a larger exodus from North African countries.
It is thought to be one of the biggest arrivals since a steady influx of Tunisians started in mid-January, when an uprising ousted the country's long-term president President Zine al-Abidine Ben Ali.
Facilities on the island are being seriously overstretched - its reception centre only has beds for 850 people.
The Italian authorities are moving the migrants by plane and boat to holding centres on the Italian mainland.
Prior to this arrival, more than 6,000 Tunisians had reached Lampedusa, reports say.
In an interview with the French paper Journal du Dimanche on Sunday, Libyan leader Col Muammar Gaddafi warned that if he fell: "You will have immigration, thousands of people from Libya will invade Europe. There will be no-one to stop them any more."
Following Italy's call last week for funds and help in housing to cope with the influx, many EU governments said it was too early to predict how many people would migrate to mainland Europe.