At least eight persons, including two women, drowned and more are feared trapped as a private bus with around 40 passengers fell into a river near Kottayam on Tuesday.
Rescuers from the Meenachil River at Thazhathangadi have fished out eight bodies while efforts were on to lift the bus from the water, police said.
Naval divers from Kochi have joined the rescue operations.
At least 19 persons, who either swam to safety or were rescued, are under treatment in various hospitals. Their condition was stated to be out of danger, police said.
The exact toll would be known only when the bus, portion of which got stuck in the muddy riverbed, is lifted out.
The bus coming to Kottayam from Cherthala first hit an electric post and plunged head on into the deep river.
Four of the deceased had been identified; hospital sources said adding the conductor of the bus was among the dead.
Rajan, a survivor, said the vehicle was travelling at normal speed along the narrow road. It hit the electric post, went out of control and fell into the river.
"I cannot say how I escaped, except that it was due to grace of God," said Rajan, who managed to come out through the backdoor as he was sitting in the rear seat.
He put the number of passengers in the bus at the time of the mishap at 35 to 40.
Kerala Home Minister Kodiyeri Balakrishnan said entire official machinery had been geared up for rescue work. Ministers of Transport, Health and Public Works rushed to the spot on hearing the news.