An Italian coast guard spokesman says it has rescued hundreds of migrants whose boat stalled after leaving Libya.
But there are unconfirmed reports of dozens of migrants dying during the journey.
Antonio Morana says the first coast guard boat with some of the migrants aboard is expected to reach Italy's Lampedusa island off Sicily Thursday night.
The ANSA news agency has reported about 300 migrants were rescued. But Morana says the exact number has yet to be determined.
ANSA cited one of the migrants who had been brought to Lampedusa by helicopter as saying that about 100 others died on the way from Libya, with their bodies being tossed overboard.
Morana said he could not confirm the reports. He added it was unclear when the boat with migrants from sub-Saharan Africa had left Libya.