At least 22 Indian people, mostly children, have died and dozens left in a critical condition needing hospital treatment after apparently being poisoned by a primary school meal.
The incident has triggered violent protests and angry allegations of blame.
School principals in India's Bihar state have been ordered to taste test food before it's served to students.
The children aged four to 12 fell ill on Tuesday after consuming a lunch of rice, soybean and lentils in the state of Bihar, one of India's poorest.
The school, at Mashrakh village 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.
Medical teams treating the children said they suspected the food had been contaminated with insecticide.
"It appears to be a case of poisoning but we will have to wait for forensic reports ... Had it been a case of [natural] food poisoning, so many children would not have died," Poonam Kumari, a local government administrator at the village, told the Reuters news agency by phone from Mashrakh.
Kumari said bodies of the victims had been cremated, adding that the remainder of a total of 48 children who consumed the contaminated food were being treated in Patna, the capital of Bihar.
"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, a medical superintendent at the children's hospital in Patna.
"We prepared antidotes and treated the children for organophosphorous poisoning," he said.
Probe under way
Organophosphorus compounds are used as pesticides.
The state government said it was investigating the cause of the disaster.
The meal was cooked in the school kitchen.
|Al Jazeera's Karishma Vyas reports from New Delhi
The school headmistress fled after the deaths became known and was dismissed, P K Shahi, Bihar's education minister, told a news conference.
"In spite of the cook's complaint [over the smell of cooking oil used for the food], the headmistress insisted on its use and the cook made the food. The children had also complained about the food to the cook," Shahi said.
The cook, who also fell ill after eating the food and was hospitalised, told Reuters television it had looked as if there was a layer of residue at the bottom of the oil jar.
"I thought that this is locally-made oil as often there is an accumulation of residual waste at the bottom ... generally we get just about enough oil to prepare one meal, as there is no space for storage," Manju Devi said.
Opposition parties accused the Janata Dal party-led government of acting too slowly to hospitalise the children and dozens of people took to the streets to protest, television channels showed.
Protesters pelted a police station with stones, set ablaze buses and other vehicles, chanted slogans denouncing the state government and burned effigies of Nitish Kumar, Bihar's chief minister
"I feel that the government completely failed vis-a-vis the evacuation of the affected children," said Rajiv Pratap Rudy, a spokesman for the main federal opposition Bharatiya Janata Party (BJP), said.
"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."
Three of the children being treated in the hospital were in critical condition, doctors and Shahi said.
Chief minister Kumar has ordered an inquiry into the incident and has offered $3,400 to the families of those who have died, Shyam Rajak, Bihar's food minister, said.