The authorities in Mauritania say they have uncovered more than 30 illegal migration networks and repatriated around 4,000 people to various West African countries.

Interior Minister Mohamed Salem Ould Merzoug told local media that there had been an increase in the number of people trying to reach Spain’s Canary Islands – an alternative route to the Mediterranean Sea where some migrants have been deterred by stricter controls and instability in Libya.

The UN has called for greater efforts to disrupt people-smuggling rings, after more than 140 people died off the coast of Senegal in October – the deadliest shipwreck of the year.