The migrants had set off in two trucks from the uranium mining town of Arlit in northern Niger towards Tamanrasset in Algeria in mid-October, officials said.
After one of the trucks broke down, the second turned back to find help but found itself stranded and the passengers attempted to make it back by foot.
The mayor of Arlit, Maouli Abdouramane, said 92 bodies had been recovered after days of searching—52 children, 33 women and seven men.
“The search is still going on,” Abdouramane told Reuters by telephone. He said the victims were all from Niger, but their final destination was unclear.
A military officer said about 20 people survived the ordeal. Five of those walked for dozens of miles across the burning desert back to Arlit to inform authorities.
The bodies were strewn across the desert over a large distance, to within 12 miles (20 kilometers) of the border with Algeria, a second military source said.
The death toll rose after Reuters reported on Tuesday that 10 people died and 50 were missing after the accident.
Most of the people who use the perilous route across the dunes are young African men in search of work in Europe or North Africa, raising questions about the purpose of the doomed convoy of women and children.
Many people leave the underdeveloped north of Niger, ranked by the United Nations as the least developed country on earth, each year in search of work.
The trafficking networks which send trucks across the desert from northern Niger to north Africa attract scores of migrants from across West Africa, even from booming economies such as Ghana, dreaming of a more prosperous life in Europe.
More than 32,000 migrants have arrived in southern Europe from Africa so far this year although it was not known if that was the intended destination for this group.
While a crackdown by Spanish authorities has largely closed a route from the West African route to the Canary Islands, many migrants seek to make the Mediterranean crossing from north Africa to southern Europe, many of them losing their lives.
Two separate incidents in southern Italy this month underscored the dangers involved when 366 Eritrean migrants drowned in one disaster and about 200 were missing after another boat sank just over a week later.