Two UN agencies are calling for greater action to dismantle smuggling and trafficking networks following the deaths of 27 migrants off the coast of Mauritania, northwest Africa.
According to the first ever Global Study on Smuggling of Migrants, released by the UN Office on Drugs and Crime (UNODC) on Wednesday, at least 2.5 million migrants were smuggled during the course of 2016.
More than 6,000 migrants have been rescued from the Mediterranean Sea after leaving the North African coastline at the weekend.
The number is not a record, according to the International Organization for Migration (IOM), but it is an indication that the sailing season has begun in earnest.
Reports have also emerged that armed gangs have targeted migrants on the high seas, robbing them of their mobile phones and boat engines.
Daniel Johnson spoke to the IOM's Joel Millman.
Duration: 4'34"
During 2016, more than 117,000 refugees arrived in war-stricken Yemen, according to the UN Refugee Agency (UNHCR), despite the escalating conflict there.
Many were lured by smugglers to take a perilous boat journey from Africa across the Gulf of Aden, or the Red Sea, in search of a better future.
UN figures released on Wednesday show that an estimated 17 million people in Yemen are going hungry and more than 2 million have been displaced.
The death toll among refugees and migrants attempting to cross the Mediterranean Sea has reached an all-time high, the UN Refugee Agency (UNHCR) has reported.
At least 3,740 lives have been lost so far this year compared to 3,771 for the whole of 2015, the highest number on record.
Many of those making the journey have been boarding from Libya in North Africa to get to Italy, a route that UNHCR considers extremely dangerous due to the open sea, strong currents and grim weather.