A group of migrant men, mainly from Niger and Nigeria, have a rest on January 22, 2019 before carrying on with their journey across the Air dessert, northern Niger, towards the Libyan border post of Gatrone. (Photo AFP)

A man looks on as he sits in the back of a pick up with other migrants mainly from Niger and Nigeria, on January 15, 2019, during a journey across the Air desert, in northern Niger, towards the Libyan border post of Gatrone. (Photo AFP)

A group of migrant men, mainly from Niger and Nigeria, have a rest next to pick up vehicles, on January 22, 2019 during a journey across the Air dessert, northern Niger, towards the Libyan border post of Gatrone.

A group of migrant men, mainly from Niger and Nigeria, sit in the back of a pick up, on January 22, 2019 during a journey across the Air dessert, northern Niger, towards the Libyan border post of Gatrone. (Photo by AFP)

A group of migrant men, mainly from Niger and Nigeria, sit in the back of a pick up, on January 22, 2019, during a journey across the Air desert, in northern Niger, towards the Libyan border post of Gatrone.

A man looks on as he sits in the back of a pick up with other migrants mainly from Niger and Nigeria, on January 22, 2019, during a journey across the Air desert, in northern Niger, towards the Libyan border post of Gatrone.

A picture taken from a vehicle and through a window shows a group of migrant men, mainly from Niger and Nigeria, sitting in the back of a pick up, on January 15, 2019 during a journey across the Air dessert, northern Niger, towards the Libyan border post of Gatrone.