People who fled the unrest in Tunisia protest against conditions on the southern Italian island of Lampedusa March 31, 2011. Italian Prime Minister Silvio Berlusconi promised to clear thousands of illegal Tunisian migrants from Lampedusa by the weekend after an outcry over a humanitarian crisis on the tiny southern island. Reuters

Refugees rioted in the Italian city of Bari on Tuesday, starting fires and attacking policemen in the street.

Hundreds of people from a local refugee camp gathered in the street, blocking roads and rail lines. Some set tires and trash cans on fire, and more than 45 were injured in clashes between the immigrants and police, including 30 Italian officers.

The refugees were migrant workers who recently fled from North Africa to Italy, hoping to find work and a better life in Europe. Since February, thousands of Africans, particularly Libyans and Tunisians, but also Somalis and other sub-Saharan Africans, have crossed the Mediterranean to Italy as violence, unemployment and famine escalated in North Africa.

The refugees rioted because they were angry at delays in getting asylum.

"They are asking for permission to stay, residency permits on humanitarian grounds," said Nicola Fratoianni, a regional immigration official, according to Euronews.

"They are almost all from sub-Saharan Africa, mostly workers in Libya, who have fled war or worse from the Gaddafi regime."

Thirty people were arrested, but the government said it would deal with the immigrants' requests by next Wednesday. It was the third riot in a week. On Saturday, eight police officers were injured outside of Rome, an event that was preceded by a 300 person riot in Sicily.

An estimated 20,000 African refugees fleeing the conflicts in Libya and northern Africa have sailed to Italy in recent months.

But the problem is not Italy's alone, and many refugees are spreading into other European countries.

"After the revolution in Tunisia, the number of migrants [in Europe] soared from the initially expected 25,000-30,000 to a million. This is a serious humanitarian problem, and it naturally generates domestic problems for each EU member state," said Dmitry Danilov, a senior analyst with the Institute of European Studies in Moscow.

"The immigrant communities are pressing for certain measures. But Europe is unable to cope with a refugee tsunami and will evidently do its best to minimize it and to reverse it."

Over the weekend, the Italian Coast guard emptied a boat from Libya on the island of Lampedusa, discovering 25 dead bodies among the 290 passengers. The men, who were refugees from Libya, died by asphyxiation when the air in the boat's hold became polluted by exhaust fumes.

Lampedusa is closer to Africa than it is to mainland Italy, and is a frequent stopping ground for African migrants heading into Europe.

In April, a boat carrying 300 Libyans capsized on its way to Italy, killing 250 people.