Unofficial sources say that the toll may go up as the administration did not have the exact list of passengers who might have boarded the bus from local stops.

The North Bengal State Transport Express bus hit the railing of a bridge while tackling an abrupt turn. The bus then plunged into the river running 60 feet below at about 2.30 am.

Later, in the evening Ghosh, who revisited the spot, informed reporters that "as there isn't any eye-witness so far, we could not immediately ascertain any specific cause for the accident".

Apparently, one of the passenger had got off at Behrampore just before theaccident. But, the identity of the passenger has not ascertained so far.

The State Government has decided to order an inquiry into the incident. It has also announced an ex-gratia payment of Rs 20,000 to the victims' family members. According to sources, Trinamool Congress leader Mamata Banerjee also visited the spot, cancelling her scheduled visit to Delhi.

Speaking to reporters at the Writer's Building, the seat of the State Government here in the afternoon, State Minister for Home (Police) Buddhadeb Bhattacharaya said, "as there were no survivors so far, barring the passenger who got down at the Behrampore, it became extremely difficult for us to ascertain the cause of the accident."

The bus officially had the capacity of carrying 51 passengers. Speaking to ENS, IG (Law and Order) Prasoon Mukherjee, said: "Right now, all we have is the reservation list of the 22 passengers who started from Calcutta on Wednesday evening."

According to Ghosh said, "Farakka Barrage authorities were instructedto stop release of water to help the rescue operation."