Milan, Italy (CNN) -- Rescue crews continued their search Thursday for more than 200 people after the boat they were in capsized in the Mediterranean Sea.
The boat was carrying about 300 people, survivors told rescue officials, according to Italian Coast Guard spokesman Cosimo Nicastro.
It sank Tuesday about 62 kilometers (39 miles) west off Lampedusa in Maltese waters, the Italian Coast Guard said.
By Thursday, officials had rescued 53 people, and recovered 15 to 20 bodies, he said.
"We are following with sorrow and concern what is happening in Lampedusa," Italian Prime Minister Silvio Berlusconi said.
Many of the survivors came from African countries, such as Eritrea, Somalia and Niger, the Italian daily newspaper, Corriere della Sera said. Many others were fleeing the war in Libya, the newspaper said.
The incident is the latest in a number of tragic ends in what has become a steady flow of people who set sail from Africa -- especially Tunisia -- to the Italian island of Lampedusa.
According to Demetrios Papademetriou, president of the Migration Policy Institute, more than 22,000 migrants have landed on Lampedusa in the past few weeks. Though owned by Italy, Lampedusa's closest shore is Tunisia.
"Of course, it's a crisis, but the Europeans do not want to call it a migration crisis," he said.
According to International Organization for Migration, the majority of unauthorized immigrants arriving in Lampedusa are Tunisian.
Some 2,000 other African migrants have arrived on the island after sailing from the Libyan coast, the agency said.
A popular uprising in Tunisia led to the ouster of its president, Zine al-Abedine Ben Ali, in January. While protesters succeeded in spurring a regime change there, many Tunisians are not seeing the kind of transformation they were imagining.
Italy's foreign minister has estimated as many as 300,000 Libyans could try to leave and could potentially end up in his country.
CNN's Mariano Castillo, Neil Curry and Lisa Sylvester contributed to this report.