NEW DELHI - At least 21 children, all below 12 years, are now confirmed dead due to food poisoning after eating a free mid-day school meal in the eastern Indian state of Bihar Tuesday, a senior police official said Wednesday.

"Some 100 children consumed the free meal at state-run Navsrijit Primary School in Masrakh village in the state's Saran district Tuesday. The death toll is likely to go up as dozens of others, who have fallen sick after having the food, are now battling for their lives at various hospitals," he said.

Bihar's Chief Minister Nitish Kumar has ordered a high-level probe into the incident and announced a compensation of 200,000 Indian rupees ($4,000) each to the families of the dead children.

The children were served with rice, dal (cooked pulses) and vegetable as part of India's mid-day meal scheme which provides free food to school children to try to boost attendance.

"It is suspected that the food poisoning may have been caused by insecticides in rice or vegetable. But, a forensic probe will bring to the fore the exact cause," the official said.

The incident has triggered massive protests in the district since Wednesday morning, with angry mobs torching police vehicles and vandalizing public property. "A huge force has been deployed in the area," he added.

India's mid-day meal scheme is said to be the world's largest school feeding program aimed at 120 million children across 1.2 million schools.