Tunisia has deployed soldiers to stop a tide of illegal immigrants trying to reach Italy, a military source has said.
It comes after Rome said a revolution in the north African country had set off a 'biblical exodus.'
More than 4,000 migrants have crossed the sea from Tunisia to the small Italian island of Lampedusa in the past week, underscoring the lingering instability in Tunisia since protests ousted its president exactly a month ago.
Catherine Ashton, the European Union's foreign policy chief, said on a visit to Tunis that she expected a trade deal with the bloc to be agreed within months, giving a boost to a Tunisian economy that has been battered by the turmoil of the past weeks.
The flow of illegal migrants sparked a diplomatic row, with Tunisia accusing Rome of infringing on its sovereignty after an Italian minister suggested sending police to Tunisia to stem the tide of people arriving on Lampedusa.
'The military are controlling the coasts at Gabes and at Zarzis to stop the illegal migrants,' the military source, who did not want to be named, told Reuters.
'The military along with the coastguards are also present at the port of Gabes.'
The Gulf of Gabes is a favoured launching point for the trip to Lampedusa - often made in overcrowded boats - while migrants were paying people smugglers $1,800 to cross from Zarzis, the International Organisation for Migration said.
Tunisian protestors unseated authoritarian ruler Zine al-Abidine Ben Ali on 14 January, in an uprising that served as an inspiration for the revolt in Egypt which on Friday forced President Hosni Mubarak to resign.
Since Ben Ali's departure, Tunisia's interim government has been making faltering steps towards stability. But police have melted away in many places, and strikes and protests around the country are disrupting the economy.
Speaking yesterday, Italian Interior Minister Roberto Maroni, a member of the anti-immigrant Northern League, said the turmoil in Tunisia had triggered a 'biblical exodus' to Lampedusa.
'I will ask the Tunisian foreign minister for authorisation so an Italian contingent can intervene to block the influx. The Tunisian system is collapsing,' Maroni said on Italian television.