More than 40 West African migrants died in the Sahara desert this week after their truck broke down in arid northern Niger, the Red Cross said on Wednesday.
The Red Cross, which said "at least 44 migrants have died," has dispatched a team to the site "to gather information" on the circumstances.
"The number of migrants who died in the desert is 44 for now," said Rhissa Feltou, the mayor of Agadez, a remote town on the edge of the Sahara that has become the smuggling capital of Africa.
A security source who asked not to be named said "the sub-Saharan migrants, including babies and women, died of thirst because their vehicle broke down."
Six survivors walked to a remote village where they said that 44 people, mostly from Ghana and Nigeria and including three babies and two other children, died of thirst, said Lawal Taher, the department head for the Red Cross in the Bilma region.
The number of migrants who cross the Sahara has increased in recent years as impoverished West Africans risk their lives to try to reach Europe.
In one of the most perilous parts of the journey, thousands of migrants each week are crammed into pickup trucks for the days-long ride from Niger into Libya, often with only enough room for a few litres of water.
Authorities and aid organisations are able to keep track of the thousands of migrant deaths in the Mediterranean Sea between Africa and Europe, but is it almost impossible to know how many have died in the vast and unpoliced Sahara.
Last year, a report by 4mi, an affiliate of the Danish Refugee Council, reported that it is likely that more migrants die in the desert than at sea, according to testimony from migrants.