At least 18 people, including some school children, were killed in a major road mishap in the western Indian state of Maharashtra Wednesday, a senior police official said.

"The mishap happened when a state-owned bus, carrying over 55 passengers, plunged into Purna river in the state's Buldhana district. The death toll is likely to go up as rescuers have been trying to recover more bodies from the river," he said, on condition of anonymity.

A number of school children were traveling on the bus, operated by the Maharashtra State Transport Corporation, when the mishap happened in the district which is some 500 km from state capital Mumbai.

"While 17 bodies have been recovered so far, a teenage girl died on the way to hospital. Those injured in the incident have been admitted to a local hospital where the condition of some are said to be serious," the official said.

A probe has been ordered into the incident, he added.