Thousands of north Africans have arrived on the southern Italian island of Lampedusa over the last few days [EPA]
Italy has declared a humanitarian emergency after thousands of migrants sailed across the Mediterranean Sea from Tunisia, overwhelming authorities on Lampedusa, a tiny Italian island.
The Tunisian government rushed security forces to coastal areas on Sunday to stop the exodus of people, a government source told the AFP news agency.
Maritime security forces "have arrested many people trying to cross the borders. Reinforcements have been sent", said the official, on condition of anonymity.
Earlier, the Italian government had said that it was planning to deploy security forces on Tunisian soil to stop the waves of illegal immigrants.
"I will ask Tunisia's foreign minister for authorisation for our forces to intervene in Tunisia to block the flux," Roberto Maroni, Italy's interior minister, said in a television interview.
He said that the EU had not responded to Italian calls for assistance, and that his country would have to manage the crisis.
Bernardino De Rubeis, Lampedusa's mayor, called the situation "out of control".
The remarks came a day after the Italian government said in a statement: "The cabinet today... has proclaimed a state of humanitarian emergency following the influx of the large number of citizens from North Africa."
The statement said that the decision to call an official emergency would enable civil protection officers "to take immediate action needed to control this phenomenon and assist citizens who have fled from North Africa".
In particular, the move will enable the central government to release funds for local authorities in areas which have been inundated by the wave of refugees, most of whom have fled to Lampedusa.
The majority of the people have come from nearby Tunisia, in the wake of the country's revolution four weeks ago.
Nearly 4,000 migrants have landed in Italy since Wednesday, according to Antonio Morana, harbour master on the island.
Most were packed into small fishing boats that were intercepted by coast guards and then taken to Lampedusa, where they were given blankets and received medical care after stepping off the boats.
Hundreds have had to sleep out in the open at the port because of a lack of facilities on the island, while others were taken to local hotels.
Karl Stagno Navarra, a journalist following events from Valletta, Malta's capital, told Al Jazeera that more migrants are on their way.
"The problem is not only for law and order on the island, but its also logistics, because the centre for migrants [on the island], which used to be operational up to a year ago ... has been closed," he said.
"The latest reports of the Italian authorities say they have identified at least another 10 boats that are expected on the island between midnight and 7am local time on Sunday."
Navarra said that up to 10,000 migrants were expected in the next week.
"So we have 4,000 migrants on an island with 5,000 inhabitants, and a structure that has a capacity to welcome not more than 800 migrants. So you can imagine the situation over there," he said.
"Throughout the night, thousands of migrants have been kept on the harbour keys, and also in the village squares. So we have a situation which is really out of hand at the moment."
Navarra said that many of the migrants say they are ultimately trying to reach France, where some of their family members are based.
The Italian authorities have organised an airlift and put a ferry into service to take some of the people off Lampedusa, transporting them to identification centres in southern Sicily.
Italy made a formal request on Friday for aid from the European Union to combat what it warned was a looming humanitarian crisis, saying that the EU's justice and home affairs council should meet immediately to discuss the matter.
In a joint statement, Maroni, the Italian interior minister, and Franco Frattini, the foreign minister, also requested "the immediate deployment of a Frontex mission for patrolling and interception off the Tunisian coast", referring to the EU's border security agency based in Warsaw.
Maroni has blamed the influx on the Tunisian authorities, saying they were unable to enforce bilateral accords on curbing illegal immigration after the weeks of protests and political turmoil in the country.
TAP, the official Tunisian news agency, said a young Tunisian migrant had drowned, and another was reported missing, when a boat carrying 12 people sank on Saturday off the coast of Tunisia, en route to Europe.