Tunisian troops patrolled southern fishing ports today, controlling access and checking identities in a bid to halt a Europe-bound exodus of illegal immigrants that has alarmed Italy.

Armoured vehicles moved through the town of Zarzis and blocked entry to the port where soldiers armed with Kalashnikovs and truncheons allowed only people identified as fishermen to enter, an AFP reporter said.

Several checkpoints were also erected in the town.

The Tunisian government announced Sunday it would send in the troops as Italy called for help after about 5,000 illegal immigrants, most of them Tunisians, arrived on its tiny island of Lampedusa over five days.

The massive influx has become a hot topic for the European Union, whose foreign policy chief Catherine Ashton held talks with Tunisia's interim authorities in Tunis on Monday ahead of a later visit by Italy's Foreign Minister Franco Frattini.

"The port is well guarded, we are doing everything to block the smugglers," an army officer told AFP on condition of anonymity.

"The smugglers are stopping the activity of the port and preventing people from working," he said.

Troops backed by coast guard vessels also worked around the port of Gabes, further south, setting up a control centre and working to prevent people from trying to cross the Mediterranean, according to the official news agency TAP.

Hundreds of youths from southern towns of Zarzis, Ben Guerdane, Tataouine, Medenine and Gafsa, all of them with a high jobless rate, have tried to illegally enter Europe in recent days in search of work.

"I am trying to persuade my children not to leave," said a Zarzis resident who only gave his name as Mohamed.

"If I have to, I will sell everything that I possess. I do not have much but I will fight for them to stay with their family," he said.

The wave of emigration comes despite Tunisia's so-called "Jasmine Revolution" a month ago, where massive anti-government protests ousted longtime strongman Zine El Abidine Ben Ali, raising the hopes of many that a page was turning for this north African country.

But not those of 29-year-old former prisoner Muhamed Handoula, who survived the capsizing of an overloaded boat of would-be migrants bound for Italy on Friday.

"A friend of mine drowned as he gripped my neck," Handoula said, showing a journalist the marks from the experience. He was saved by a fisherman, he said, after six hours at sea holding on to the boat's motor.

"If I could do it again, I would," Handoula said. "There is no place for me in Tunisia. The Tunisian revolution was just talk."

Italy has warned of a humanitarian crisis after an increase in the influx of migrants in the month following Ben Ali's ouster on January 14.

It has called for help from the EU and said it wants to send its own security forces into Tunisia to halt the migrants, a suggestion that Tunis angrily rejected.

The quiet southeastern coastal town of Zarzis, with its blue and white buildings, suddenly has been catapulted front and center of the migration debate.

For years, Zarzis and the arid surrounding region have eked out a living on fishing, olive oil and tourism.

"It's Ben Ali's politics that created an unequal distribution of wealth and sparked a high unemployment rate," driving the exodus, said Shamseddine Bourassine, head of the local fishing union.

Whatever the cause, 18-year-old Addallah Aloutwiti has given up hope of a better life here.

"We work like animals for 10 dinars (five euros, $7) a day," Aloutwiti said. "For the next 50 years, there is no hope for us."