The migrant flight was prompted by clashes between police and protesters in Tunisia that forced its president, Zine El Abidine Ben Ali, to flee to Saudi Arabia on Jan. 14, and inspired the uprisings in Egypt and beyond.
Some 2,000 of the 5,337 Tunisians who arrived in recent days remained on Lampedusa, a tiny island with a permanent population of about 6,000 that is closer to Africa than the Italian mainland, awaiting transfer to immigrant holding centers elsewhere in Italy.
"We want to thank all the Italians and the people from Lampedusa because they gave housing and food to 5,000 people and they were very nice to us," said Zawhir Kermiti, a 32-year-old who was one of a few dozen people who marched Tuesday. He and others arrived in Sicily in fishing boats from Tunisia.
Overnight, Italian authorities intercepted a boat of 32 people believed to be from Egypt off the coast of Ragusa on Sicily, indicating that the exodus was not confined to Tunisia alone.
"The institutional earthquake that took place in Egypt could provoke significant immigration flows," Italian Interior Minister Roberto Maroni warned Tuesday. "Europe cannot remain indifferent: it must take a strong and decisive political decision."
Italy has arrested 26 people who operated the boats and seized 41 vessels. Identity checks have found some of the arrivals were criminals who escaped from Tunisian jails in the chaos, Maroni said.
He spoke at a news conference in the Sicilian city of Catania, where he and Premier Silvio Berlusconi toured a NATO military residence with a capacity of 7,000 people that the government is considering turning into a "village" for possible asylum-seekers.
Lampedusa Mayor Bernardino Rubeis has said that the Tunisians have mostly been respectful and that the situation is under control.
"There is no security emergency because they are free to walk around the island, but they are respecting our territory, not creating any trouble," he said.
On Tuesday, many of new arrivals awaited ferries to take them from Lampedusa to immigrant holding centers elsewhere in Sicily or on the Italian mainland.
"It took 30 hours from Djerba to here. It wasn't very dangerous. We were 260 people on this boat," said Samir, a 24-year-old Tunisian who asked not to give his last name. Djerba is an island located off the coast of Tunisia.
He spoke as he and others picked through the wreckage of their fishing boats that have been hauled out of the harbor and piled in a sort of boat cemetery near a soccer field. Among the debris in the boats are blankets, gloves and cell phone battery chargers.
No boats arrived overnight on Lampedusa, primarily because of poor weather.
But Maroni, who has said the exodus was of "biblical" proportions, said he had no illusions that the onslaught was over.
"So far, the (Tunisian) border controls have stopped four boats and turned them back, but 47 more escaped the controls," Maroni said.
He said he planned to meet with his counterparts in France, Spain, Malta, Greece and Cyprus in the coming days to decide on further immediate measures to take. He said Italy alone needed some euro100 million from EU funds to confront the emergency over the next three months.
EU Commission spokesman Michele Cercone said the EU had received a letter from Italy listing its needs and that the EU was looking to give Italy aid through its refugee and border fund.
On Monday, the EU announced a euro258 million ($347 million) aid package to Tunisia from now until 2013, with euro17 million ($22.9 million) of that to be delivered immediately. EU foreign policy chief Catherine Ashton, visiting Tunisia, said the funds were a gift, not a loan.
Italian Foreign Minister Franco Frattini met with Tunisian authorities Monday night in Tunis and concurred that Tunisia was responsible for patrolling its coast but that European border agency Frontex should beef up its presence in international waters. Tunisia had strongly rejected an offer by Maroni for Italian police contingents to help patrol the coast.
EU Home Affairs Commissioner Cecilia Malmstroem late Tuesday declared the exodus a "matter of importance for the whole EU," and said Frontex had sent two experts to the scene.
Frattini said Italy cannot accept everyone who arrives, but at the same time must help Tunisia and other North African countries create conditions so young people don't feel the need to flee.
"We can't package them up and send them back home," Frattini said Tuesday. "We have to help them reintegrate themselves" with economic help.
After his visit, Tunisia's TAP news agency reported that Italy would provide euro5 million ($6.8 million) in emergency aid to Tunisia, as well as radar equipment and patrol boats to the Tunisian military, and offer a euro100 million ($135 million) credit line.
It's unclear whether this is part of the overall EU package announced Monday.
AP reporters Nicole Winfield in Rome, Raf Casert in Brussels and Bouazza Ben Bouazza in Tunis contributed to this report.