More than 100 children have been killed by lead poisoning as a result of illegal gold minining in northern Nigeria.
Authorities in Zamfara state say a total of 163 people have died in several remote villages since March.
More than 200 others have been taken ill.
Many of the victims died after touching tools,
soil and water contaminated with large concentrations of lead.
Authorities have stopped the illegal mining and have begun evacuating some residents.
International aid agencies, including the World Health Organisation and the U.S. Centers for Disease Control and Prevention, are assisting Nigerian authorities in containing the
outbreak in four villages.