Nearly 20,000 migrants have been rescued from the Sahara desert in Niger over the past three years, the International Organization for Migration said on Tuesday.
The IOM said that on June 15 alone it rescued 406 migrants from 14 West African countries, including seven women and four children.
"We walked for hours under the scorching desert sun with no water or idea where we were heading," the IOM quoted Amadou, a 27-year-old from Mali, as telling rescuers.
The UN organisation said the most recent rescues had mainly included people from Ivory Coast, Guinea-Conakry and Mali.
"Despite having assisted so many groups of migrants, I still find it difficult every time a new group arrives, with newborns in their arms, faces covered in sand and their clothes ripped apart," said Alhassane Adouel from IOM.
"After so many arrivals, it still breaks my heart to see what they have to go through."
Trucks carrying migrants north frequently breakdown in the desert or become lost, with smugglers sometimes abandoning people to their fates, the IOM said.
No one knows exactly how many migrants have died attempting to cross the Sahara, often due to hunger or thirst.
The latest operation was IOM's 189th humanitarian mission into Niger's Tenere desert, the most remote desert in the Sahara.
The vast plain of sand spans an area larger than Japan.
Rescued people are taken to reception shelters where they receive food, first aid and counselling, IOM said.
The IOM said it had rescued nearly 20,000 people from the Sahara since April 2016.
The flow of migrants, often heading for Libya with the ultimate aim of reaching Europe, has lessened considerably since a 2017 peak.
Niger President Mahamadou Issoufou in May said the number of migrants traversing his country had dropped from 150,000 a year to fewer than 10,000 after efforts to stem the flow, including anti-trafficking legislation.