NEW DELHI, July 21 (Xinhua) -- At least 15 children were injured after their school van fell off a bridge in the central Indian state of Chhattisgarh, police said Saturday.

The accident occurred in Korba district, some 230 km from state capital Raipur.

"The van carrying the 15 school children skidded off the road and fell off the bridge on to a muddy field. All the school children have been hospitalized," a police official said.

The condition of four of the injured children are said to be serious, he added.

"A probe has been ordered into the incident. The van driver has also been arrested and booked for rash and negligent driving," the official said.

India has one of the highest numbers of road fatalities in the world. Road accidents occur mostly due to poor driving or badly maintained roads and vehicles.