They were heading to Europe before traffickers made them work in illegal gold mines, authorities claim.
Scores of EU-bound child migrants have been rescued from forced labour and criminal networks in Sudan, police say.
Interpol, which coordinates collaboration between police forces across the world, says 94 people were saved in and around the capital Khartoum.
The crackdown, which was led by the Lyon-based organisation, found dozens of children being forced to work in illegal gold mines. Youngsters as young as 10 were handling dangerous chemicals there, Interpol said on Monday.
Sudan is a source and transit country for African migrants hoping to reach Europe via Libya and the Mediterranean, according to the International Organization for Migration.
Tim Morris, Interpol's executive director of police services, said many of the victims had been travelling to Europe when they fell into the hands of human traffickers.
"We believe that they were transiting through Sudan and then kidnapped en route and diverted into these forced labour activities," Morris told Reuters.
The victims came from Chad, Democratic Republic of Congo, Eritrea, Niger, Sudan and South Sudan, he said.
Sudan has one of the world's highest rates of slavery — with about 465,000 people enslaved or one in 80 of its population — the 2018 Global Slavery Index found.
Children separated from their parents or travelling alone are at a high risk of exploitation, sexual and physical violence, said a spokeswoman for the IOM office in Sudan.
"In many cases these children are exposed to forced unpaid labour including street begging, gold mining, street vending, agriculture and other hazardous working conditions with limited access to education, protection and health services," she said.
Interpol said 14 suspected traffickers had been arrested in the operation.