A boat packed with migrants from Africa overturned in the Mediterranean Sea on Wednesday, pitching passengers into the water, the Italian coastguard said.
About 700 people had been aboard the boat, an international broadcaster said. Italian and Irish naval vessels were trying to rescue survivors.
A coastguard spokesman confirmed that an overcrowded boat overturned off the Libyan coast just as ships came to its rescue.
However, he could not say how people were aboard or how many had been saved because the operation was still going on.
The Mediterranean Sea is the world’s most deadly border area for immigrants.
No fewer than 2,000 migrants and refugees have died so far in 2015 in attempts to reach Europe by boat.
This is compared with 3,279 deaths during the whole of 2014, the International Organisation for Migration said on Tuesday