There has been a sharp increase in the number of African migrants arriving in Italy in overcrowded boats, officials say.
More than 3,000 people have reached the small island of Lampedusa - 200km (124 miles) off the Tunisian coast - in the past few days, they report.
Arrivals are said to include Somalis and Nigerians as well as North Africans fleeing the violence in Libya.
Recent good weather has also been a factor, correspondents add.
On Tuesday night, the Italian coastguard intercepted a boat with 300 migrants including women and children.
Death at sea
The United Nations High Commission for Refugees (UNHCR) said 52,000 people had arrived in Italy from North Africa since the start of the year.
More than half left Libya, although there were few Libyan nationals among the arrivals.
The UNHCR also reported this week that more than 1,500 people had died at sea trying to make the journey in poorly maintained and overcrowded boats.
UNHCR spokesman Adrian Edwards said 200 women and 30 children from Libya and Tunisia had been among last weekend's arrivals.
"They had waited for over a week for calm sea conditions to depart," he told a news briefing in Geneva.
In April, the International Organisation for Migration (IOM) said the tiny island of Lampedusa had been "overwhelmed" by migrants arriving since the start of the year.
Fortress Europe, an Italian-based organisation that monitors migration, also said this week that as many as 1,931 migrants had died in the Mediterranean in the first seven months of 2011.
It described Lampedusa as struggling to deal with last weekend's influx.
Italian Prime Minister Silvio Berlusconi promised in April to clear Lampedusa and move new arrivals to reception centres in other parts of Italy and also to speed up repatriation agreements with Tunisia.
However, thousands of refugees have arrived since then from both Tunisia and Libya as border controls crumbled after the Nato bombing campaign against Libyan leader Col Muammar Gaddafi.
Meanwhile, Italian news agency Ansa reports that a group of Tunisians set fire to mattresses in a migrant centre in Sicily this week.
In another incident in nearby Malta on Tuesday, migrants from northern Africa threw stones and other objects at police officers and soldiers as a protest against detention centre conditions escalated into violence.