The incident took place this morning when the driver lost control over the vehicle and it fell into the Kalvi River, they said.
Although the number of students travelling in the bus is not clear, locals claimed that there were atleast 15 of them.
A major rescue operation was initiated immediately after the mishap and fire brigade as well as police divers were rushed to the spot.
The driver and conductor are safe as they jumped out when they lost control. But there has been no official confirmation about any deaths and searches are on for the missing children.