* Tensions rise on island overwhelmed by migrants
* Berlusconi promises to complete transfers by weekend
* He urges Italians to be hospitable
(Changes dateline to Lampedusa, adds statement from PM office)
By Leon Malherbe
LAMPEDUSA, Italy, April 2 (Reuters) - Italian Prime Minister Silvio Berlusconi tried on Saturday to calm North African migrants on the island of Lampedusa, promising to send them to better camps this weekend and urging Italians to be hospitable.
More than 20,000 immigrants, mainly from Tunisia, have reached the Italian island in recent weeks, transforming a quiet tourist and fishing port into a garbage-strewn encampment.
The length of time that it takes to transfer them elsewhere in Italy has sparked anger among the migrants, and among the 5,000 islanders, who feel increasingly overwhelmed.
A caravan previously used as a ticket booth in the port was set on fire on Saturday and some of the more than 3,000 migrants waiting to be shipped to other camps threatened a hunger strike over the delays.
“We have to be understanding and hospitable, because we are a civil and a Catholic country,” Berlusconi said in a telephone call to a political meeting in Sicily on Saturday.
“By tomorrow at the latest, Lampedusa will be given back to its citizens.”
A statement from Berlusconi’s office said that, despite strong winds and choppy seas, an Italian naval ship was taking on board 500 migrants to take to a camp on the mainland.
Once weather conditions improve, another ship is due to transfer a further 1,700 migrants, the statement added.
It said the food and water available to the migrants had been checked and deemed adequate.
Amnesty International on Friday accused the Italian government of failing to provide the migrants with adequate shelter and sanitation.
The Medical charity Doctors Without Borders said migrants were receiving just 1.5 litres of water per person per day, compared with recommended standards for refugee camps of 20 litres.
“People stay here 10 days, don’t sleep well, don’t eat well, sleep on the street, no showers, no clean clothes, nothing,” Tunisian migrant Saber said as he waited to be transferred off Lampedusa on Saturday.
“People here would like to go to another country, they have family, friends, they want to work, find jobs, be there, because in Tunisia and Libya the situation is no good,” Saber added.
But as migrants have moved on, problems have sprung up at camps elsewhere in Italy, and the government has struggled to come up with a longer-term response.
Hundreds of migrants have escaped from a camp in Manduria in southern Italy, where one tried to set himself on fire on Saturday but was stopped by police, according to media reports.
Berlusconi, who visited Lampedusa on Wednesday, says Italy is being left alone to face what should be a European problem.
He is due to visit Tunisia on Monday with Interior Minister Roberto Maroni and has said he will demand that it do more to stop migrants leaving, and accept those sent back by Italy.
Maroni, from the anti-immigrant Northern League, has complained of a “total refusal to cooperate” by Italy’s neighbours and the European Union, and said Rome may make it easier for immigrants to move on to France and Germany.
French Prime Minister Francois Fillon told the Italian daily newspaper Corriere della Sera on Saturday that France agreed with Italy’s position that the only solution was to send the migrants back and that Europe should support Italy financially.
The Northern League plans to hold a demonstration on Sunday in the border town of Ventimiglia to protest against France’s rejection of migrants seeking to enter from Italy. (Additional reporting by Catherine Hornby in Rome; Editing by Kevin Liffey)