As many as 26 children are feared killed and 10 seriously injured after a school bus collided with a speeding train at a level-crossing gate.

The bus, which was carrying 40 students, was completely damaged as it was hit by the train, which was heading to Secunderabad in the newly-formed southern state of Telangana.

The accident happened at Masaipet in Medak district, about 70 km from Hyderabad. The bus belonged to the Kakatiya Techno School.

The injured, some of them seriously, have been admitted to a local hospital. Police sources say the death toll could rise.

Such was the impact of the collision that the bus is reported to have been dragged for at least 1km by the train.

Schoolbags and water-bottles are said to be lying scattered around the wreckage of the bus.

There are conflicting reports about the cause of the accident. Some reports say the driver of the bus, who was among those killed, failed to heed a warning about the gate being left open.

Other reports indicate that due to technical lapses, the signal at the level-crossing failed.

"We are investigating the cause of the accident and whose mistake it is," deputy inspector general of police N Suryanaarayana said, AFP reported.

India's railway crossings have turned into virtual death traps with about 15,000 people being killed every year at the gates.

Numerous safety panels have recommended bridges and overpasses to avoid accidents, but these have only remained on paper.