The first Irish naval vessel to take part in a major operation targeting human traffickers heads for the Mediterranean today.

The LÉ Niamh will be taking part in Operation Sophia, the EU mission to capture boats used by people smugglers, and return migrants to the Libyan authorities.

Previously, Irish personnel have saved thousands of lives in the Mediterranean as part of the EU's humanitarian mission, Operation Pontus.

However Aengus O'Snodaigh, Sinn Féin's defence spokesperson, thinks Operation Sophia actually puts migrants in danger.

He said: "Operation Sophia is to turn them around or to hand them over to the Libyan Coast Guard.

"That by itself isn't as concerning, what's concerning is what the Libyan Coast Guard or the smugglers do when the refugees are retrurned to Libya.

"They are put into appalling detention centres."