Trucks Break Down

The migrants had set off in two trucks from Arlit towards Tamanrasset in Algeria some time between late September or early October, officials said.

After one truck broke down, the second turned back to look for help but was stranded and the passengers tried to return by foot. It was weeks before authorities were alerted and able to reach the site.

"Sometimes in the vast desert, there are tragedies like this which are never even discovered," government spokesman Marou Amadou told state television.

"So the government has instructed administrative authorities and defence forces to put an end to this transport which kills."

Authorities said all the passengers came from the region of Kantche in southern Niger, 700 km east of the capital Niamey.

Many people emigrate to flee poverty in Niger, ranked by the United Nations as the least developed country on earth. Some work in neighbouring Libya and Algeria to save money before returning home.

The networks which send trucks across the desert also attract migrants from other countries in West Africa who dream of a more prosperous life in Europe.

Many of the people-smugglers are from nomadic groups who have seen their traditional pastoral lifestyle destroyed by droughts since the 1970s, according to a UN report published in February.

More than 32,000 people have arrived in southern Europe from Africa so far this year.

A crackdown by Spanish authorities has largely closed a route from the West African coast to the Canary Islands which drew tens of thousands of migrants in the mid-2000s.

Instead, most now try to make the Mediterranean crossing from north Africa to southern Europe, many losing their lives when their rickety boats are wrecked.

More than 500 people are believed to have died in two shipwrecks off southern Italy this month.