Niger has 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.
A security source told AFP news agency on Saturday that Niger had detained at least 100 migrants, mostly men but also some children, on their way to Algeria.
In a statement read on public television on Friday, the government 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 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," the government said as it announced the closure of the "ghettos", the name given to migrant camps in Agadez, the main town in northern Niger.
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.
Only 21 people survived out of 113 trying to cross Niger's desert border into Algeria in two trucks, which both broke down.
'Thirst is merciless'
The victims "died of thirst, since their two vehicles almost simultaneously broke down", Rhissa Feltou, the mayor of Agadez, 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," he added.
The bodies were discovered in small groups "in a radius of 20km", said Almoustapha Alhacen of the non-governmental organisation Aghir In'man ("Human Shield" in the language of the ethnic Tuareg people of the desert).
The last disaster on such a scale was reported in May 2001 in Libya, back when it was ruled by Muammar Gaddafi and was a regional economic hub. On that occasion 140 people were found dead of thirst in the desert.
Since the fall of Gaddafi 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.