40 children of the Kakatiya Techno School in Toopran town were in the bus when the accident took place in the Medak district, 70 kms from the state capital of Hyderabad. After the bus was hit by the train, witnesses say it was dragged several metres down the tracks.
The police say 16 children aged 7 to 14 have been injured in the accident and hospitalized.
Schoolbags and water-bottles lay scattered at the site of the accident as rescue workers pulled out children. Distraught parents crowded the site, some mothers holding children they had prepared for school just an hour before. One mother was seen kissing her child, shock and disbelief apparent on her face.
The police believe the driver tried to cross the track despite warnings of the advancing train, which was travelling from Nanded in Maharashtra to Hyderabad in Telangana, carved out of Andhra Pradesh last month.
Prime Minister Narendra Modi expressed condolences and Chief Minister K Chandrasekhara Rao has ordered an inquiry.
About 15,000 people are killed each year while crossing the tracks on India's vast but decrepit railway network, according to a government safety panel. Two years ago, it recommended that more bridges and overpasses be built at the earliest.
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