NEW DELHI, Oct. 8 (Xinhua) -- As many as 20 children have been injured after a truck rammed into their school bus in the northern Indian state of Uttar Pradesh Monday, police said.

The accident occurred at Shaktinagar in the state's Sonbhadra district.

"The bus carrying some 50 students of Central School was hit by the truck after its driver lost control of the speeding vehicle," a police official said.

Some 20 students as well as the school bus driver sustained injuries in the collision, he said, adding that they have been admitted to a nearby hospital.

"The condition of the bus driver is serious," the official said.

A probe has been ordered into the incident, he said. "A case of rash and negligent driving has been registered against the truck driver who fled the spot after the accident," he added.

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