NIAMEY: Rescuers have found the decomposed bodies of 87 migrants in the harsh Niger desert, some of them eaten by jackals, local officials said, the country's worst such tragedy in a decade.

The victims, nearly all of them women and children, had been trying to reach neighbouring Algeria but are believed to have died of thirst when their truck broke down, according to a senior security source in Niger.

Almoustapha Alhacen, from local aid organisation Aghir In'man, gave a graphic account of the grim discovery on Wednesday about a dozen kilometres (miles) from the Algerian border.

“The corpses were decomposed; it was horrible,” he said.

“We found them in different locations in a 20-kilometre (12-mile) radius and in small groups, often under trees, or under the sun. Sometimes a mother and children, but some lone children too.”

Among the 87 bodies were 48 children, 32 women and seven men, the security official said, adding to the bodies of five women and young children found earlier.

Some of the bodies were “devoured by jackals or other wild beasts,” said Alhacen.

All died in early October after a failed attempt to reach Algeria across the inhospitable Sahara desert that covers about 80 per cent of Niger, one of the world's poorest countries.

The bodies were buried according to Muslim rites as and when they were found, added Alhacen.

Nigerien officials had said on Monday that dozens of migrants, most of them women and children, had died of thirst in the Sahara desert earlier this month.

Two vehicles were carrying the migrants when they broke down, one about 80 kilometres from the northern city of Arlit where they had set off from and another about 160 kilometres away, the security source said.

“The first vehicle broke down. The second returned to Arlit to get a spare part after getting all the migrants it was carrying to get off, but it too broke down,” said the source.

“We think that the migrants were in the desert for seven days and on the fifth day, they began to leave the broken down vehicle in search of a well,”said the source.

However, 21 people survived, the source said, including a man who walked to Arlit and a woman who was saved by a driver who came across her in the desert and took her to the same city.

Nineteen others reached the Algerian city of Tamanrasset but were sent back to Niger, the source added. Niger is one of the world's poorest countries and has been hit by successive food crises.

Libya, rather than Algeria, is more frequently the favoured country of transit for west Africans making the journey across the continent, many of whom aim to travel on to Europe.

The UN's Office for the Coordination of Humanitarian Affairs estimates that at least 30,000 economic migrants passed through Agadez, northern Niger's largest city, between March and August of this year.