The Italian coast guard found 25 dead bodies on a refugee boat fleeing Libya Monday as it crossed the Mediterranean on the way to the Italian island of Lampedusa.

Survivors told the authorities the overcrowded boat, which held almost 300 people, left Libya three days ago. Coast guard officials received a call for assistance when the boat was 56 kilometers south of Lampedusa.

The 25 dead, all of them young men, were found in the boat's engine room.

All the other immigrants on board, most of whom are believed to be from sub-Saharan Africa, were escorted to safety. Authorities are now investigating to determine the cause of death of the young men, but initial reports show they apparently died of asphyxiation.

Hundreds of people fleeing unrest in Libya and elsewhere in North Africa have died in recent months while attempting to make the dangerous crossing in rickety boats.

But thousands of fleeing refugees continue to arrive on Lampedusa. The island, Italy's southern-most point, is the biggest gateway for illegal immigration into the European Union.