At least 54 people drowned in the Narmada river in Madhya Pradesh's Dewas district last Saturday in a flash flood caused by the release of water from a dam into the river.
A majority of those killed were pilgrims taking a dip in the river on the occasion of Bhootdi Amavasya.
Of those dead, 34 were men, 17 women and three children, Dewas Superintendent of Police Virendra Singh said.
The authorities, who took two days to confirm the incident, said the toll may go up.
The local police had confirmed recovery of 35 bodies initially. Seventeen more bodies were recovered from the river on Monday.
Sources said the flash flood was caused when water was released from the Indira Sagar Dam, 100 km upstream from the bathing spot near village Dharaji, without any warning.
"While a handful of lifeguards have rescued some people, many more might have been washed away as they were sleeping or resting on the banks," an eyewitness said.
Unofficial sources put the toll at 70.
Chief Minister Babulal Gaur visited the site on Monday morning and announced a compensation of Rs 1 lakh each to the families of the deceased.
"The incident is unfortunate. Necessary action would be taken on the report of a high-level committee, which has been asked to probe the release of water," he said.
The high-level probe committee, headed by Water Resources Principal Secretary Arvind Joshi, has been asked to submit its report at the earliest.
Gaur gave instructions for arranging funeral for the recovered bodies as also to provide required facilities to their relatives.
State Bharatiya Janata Party president Kailash Joshi, Minister of State for Urban Administration and Development Shivnarayan Jagirdar, local members of Parliament, legislators and senior officials accompanied him.
Meanwhile, Joshi also made an on-the-spot assessment at the site.
The Narmada Hydroelectric Development Corporation, which operates the dam, denied it released the water without intimation.
Around 300,000 people had gathered near Dharaji village on the banks of the Narmada, around 200 km from Bhopal, for the Bhootdi fair, held in the first fortnight of April every year.
Hundreds of people have approached nearby police stations to enquire about relatives who have not returned from the fair, the police said.
"It is worse than tsunami. The tsunami was beyond human control. Here it is a cent per cent manmade tragedy. The culprits should be immediately suspended and stern action should be taken against the guilty," said state Congress general secretary Manak Aggarwal.
WITH PTI INPUTS