Niger on Friday ordered the "immediate" closure of migrant camps in the north of the country after 92 people, mostly women and children, died of thirst trying to cross the harsh Sahara desert.
In a statement read on public television, the government also announced that all those involved in trafficking migrants, many of whom pass through northern Niger on their way to Algeria or Libya, would be identified and "severely punished".
The decomposed bodies of 52 children, 33 women and seven men were found on Wednesday following their grisly death in October after two trucks carrying them broke down on the way to Algeria.
"This tragedy is the result of criminal activities led by all types of trafficking networks," government said as it announced the closure of the "ghettos", the name given to migrant camps in Agadez, the main town in northern Nigeria.
Prime Minister Brigi Rafini will pay a visit to the southern district of Kantche where most of the deceased came from, to present the "condolences of the nation wounded by this tragedy" to their families, according to the statement.
Niger's government also announced there would be three days of mourning following the tragedy.
Flags flew at half-mast on official buildings in memory of the victims, who all came from the south of the deeply poor west African country and were headed for Algeria.
Those who died were "migrants like we see them pretty much everywhere, such as in the dramas on the Mediterranean Sea," said Rhissa Feltou, the mayor of Agadez, the main town in north Niger.
Only 21 people survived out of 113 trying to cross Niger's desert border into Algeria in two trucks, which both broke down, according to a highly placed security source.
'Thirst is merciless'
The victims "died of thirst, since their two vehicles almost simultaneously broke down," Feltou said.
"In the desert, thirst is merciless. The strongest can hold out three or four days, but in general at the end of 24 or 48 hours, a swift death process ensues," the mayor of Agadez added.
The bodies were discovered in small groups "in a radius of 20 kilometres (12 miles)", said Almoustapha Alhacen of the non-governmental organisation Aghir In'man ("Human Shield" in the language of the ethnic Tuareg people of the desert).
A security source said he believed migrants had managed to survive for five days and then "began to leave the broken-down vehicle in search of a well".
A woman who originally came from south Niger and allegedly organised the fateful journey was detained by security forces in the desert town of Tamanrasset, a security source said.
The last disaster on such a scale was reported in May 2001 in Libya, which was considered an El Dorado to find work in the days of Moamer Kadhafi. Then, 140 people were found dead of thirst in the desert.
Since the fall of Kadhafi in 2011, the route via Agadez to Libya and on to Europe has gained popularity over the journey to Algeria.
More than 5,000 west Africans, many of them from Niger, took the Agadez trail each month between March and August this year, according to the United Nations.
At Saint Peter's Square in the Vatican, Pope Francis on Friday urged Christians worldwide to join him in prayers "for all those of our brothers and sisters, men, women and children, who died victims of hunger, of thirst, of fatigue on their way to find better living conditions."
"These days, we have seen pictures in the papers of the cruel desert," the pope told a crowd of 60,000 in an impromptu departure from his homily for All Saints' Day.
The pope has previously taken up the cause of people faced with poverty and violence who seek a better future and he has spoken out against the human trafficking.