At least 21 children have died and dozens more have fallen sick after eating a tainted school meal in India's eastern state of Bihar.
The poisoning occurred at a government school in the village of Masrakh in Saran district on Tuesday. Bihar is one of the country's poorest and most populous states.
An inquiry has begun and 200,000 rupees ($US3370) in compensation offered to the families of each of the dead.
India's Mid-Day Meal Scheme provides free food to try to boost attendance, but often suffers from poor hygiene, the BBC reports.
Twenty-eight sick children were taken to hospitals in the nearby town of Chhapra and the state capital, Patna, after the incident.
A total of 47 students of a primary school in Dharmasati Gandaman village fell sick after eating the free lunch. There are fears the number of dead could rise as some of the children, all below the age of 12, are critically ill.
State education minister PK Shahi told the BBC a preliminary investigation indicated that the food was contaminated with traces of phosphorous, a poisonous substance.
A doctor treating the children at a hospital in Patna said contaminated vegetable oil could have led to the poisoning.
The Mid-Day Meal is the world's largest school feeding programme, reaching 120 million children in 1.2 million schools across the country, the government said. It was first introduced for poor and disadvantaged children in the southern city of Chennai in 1925.