New Delhi  - Rescue workers kept searching for missing people as the death toll in boat accidents in two Indian states rose to 97 on Thursday, officials said.

In one of India's worst tourism-related accidents, 39 people, including 13 children, drowned when a boat capsized in a lake at the Periyar forest reserve in the southern state of Kerala on Wednesday evening.

At least 58 villagers died in another boat tragedy in Bihar, a state in eastern India.

Kerala police said a double-decker boat carrying 76 tourists overturned when passengers rushed to one side to see a herd of wild elephants. Thirty-one passengers were initially reported dead.

"Eight more bodies have been fished out of the lake overnight. Twenty others, four of them foreign tourists, swam to safety," J Radhakrishnan, a local police officer, said over phone from the area, located 280 kilometres north of the state capital Thiruvananthapuram.

"The operations, led by a team of Indian navy divers, will continue searching for the missing through Thursday," he added.

Police rejected media reports that two foreign tourists died in the incident, saying all the victims were Indian, mostly from southern states and nine from the national capital New Delhi.

Authorities in Kerala, renowned for its beautiful scenery, temples and wildlife sanctuaries, have ordered a probe into the accident.

Officials said safety norms had been flouted as the boat was carrying more than its capacity of 70 passengers and none of the tourists had been given life jackets. There was also no professional guide on board to warn tourists against moving onto one side.

Meanwhile, the death toll in the boat accident in Bihar's Bagmati river in the central Khagaria district climbed to 58 with two more bodies found by villagers since Wednesday evening.

The overcrowded boat capsized Monday evening amid torrential rain and gusty winds. The victims, all villagers, were returning from a fair marking the conclusion of the Hindu Durga Puja festival.

The victims were mostly children. "Of the 53 bodies identified, 42 were children, boys and girls," Sati Charan Jha, a district official said.

Every year, scores of people drown in boat tragedies across India. At least 29 people drowned in a similar boat tragedy in Kerala in 2002. Dozens have died when boats capsized in rivers across Bihar during this year's monsoon season. (dpa)