The bus, carrying about 40 passengers, was travelling from the state capital, Guwahati, to Kamrup district.

The incident happened when a wooden bridge that the bus was crossing collapsed and fell into the water.

Local villagers rushed to the accident site at Rajabari after the accident on May 30 night and rescued six passengers from the wreckage, reports said.

Police divers arrived at the site, where many villagers had gathered, on May 31 morning to begin the search for the missing passengers.

Bus crashes are common in India. Often caused by poorly maintained vehicles and reckless driving, they claim thousands of lives every year.