At least 22 children died and dozens were taken to hospital with apparent food poisoning after eating a meal provided for free at their school in the Indian state of Bihar, officials said on Wednesday, sparking violent protests.
Medical teams treating the children said they supected the food had been contaminated with insecticide.
The children, aged four to 12, fell ill on Tuesday after consuming a lunch of rice, soybean and pulses in the eastern state. The school, in the district of Chapra, provided free meals under the Mid-Day Meal Scheme, the world's largest school feeding programme involving 120 million children.
"We feel that some kind of insecticide was either accidentally or intentionally mixed in the food, but that will be clear through investigations," said R.K. Singh, medical superintendent at the children's hospital in the state capital, Putna.
"We prepared antidotes and treated the children for organic phosphorous poisoning."
Dozens of residents took to the streets in Chapra and Patna, television channels showed. Demonstrators pelted a police station with stones, set ablaze buses and other vehicles, chanted slogans denouncing the state government and burned effigies of Bihar Chief Minister Nitish Kumar.
The school principal fled after the deaths became known and was dismissed, Bihar Education Minister P.K. Shahi told a news conference. The initial death toll of eight shot up to 22 on Wednesday.
"As soon as my boy returned from school, we rushed to the hospital with him," said Raja Yadav, the father of one schoolboy. "He was vomiting and he said his stomach was aching."
Nearly 25 children were being treated in the hospital, with three in critical condition, doctors and Shahi said.
Kumar has ordered an inquiry into the incident and has offered 200,000 rupees ($3,400) to the families of those who have died, the state's food minister said.
Bihar, bordering Nepal, is one of the most impoverished states in India, according to government data.