Six children and the driver of their school bus died this morning when the vehicle fell into a gorge in India's Himachal Pradesh, officials said.

The incident took place around 8:00am near Kharkoli on Dadahu-Sangrah road in Sirmaur district when the bus skidded off the road. Sirmaur district is around 150 km from the state capital Shimla, reports NDTV.

Around 12 children were injured and have been hospitalised, a police official said, adding that the condition of some of them is critical.

Rescue officials were facing difficulties in pulling out the bodies from the badly-mangled bus, according to witnesses.

Three of the deceased children and the bus driver died on the spot while three others succumbed to their injuries after they were rushed to hospital, reports NDTV.

It appears that the accident happened due to the negligence of the bus driver, identified as Ram Swaroop, 40, police said.