It's still unclear how many migrants are missing from a fishing boat - which capsized in the Mediterranean yesterday.

400 people were rescued from the upturned vessel off the coast of Libya - most of which are being taken to shore by the Irish ship the LE Niamh.

But it's thought the boat was carrying at least 600.

25 bodies have been pulled from the water.

Commander Brian Fitzgerald from Naval Headquarters explains what made the rescue so difficult: