"I want my child back. No stone should be left unturned," Aisa Hussain, whose son was swept away in the flooded Beas river in Mandi district, said Tuesday.
"He should be traced at all cost. If he's not alive, I want the body of my son back," Aisa told IANS.
She is among 55 parents of 19 missing students of the VNR Vignana Jyothi Institute of Engineering and Technology in Hyderabad who have been desperately waiting to hear about their sons and daughters.
One tour operator is among the missing people.
B.V. Suba Rao, whose son is also in the missing list, said: "I fail to understand that how my son, who was a very good swimmer, was swept away."
He said most of the children who drowned were brilliant.
"In this high-tech world, there are many devices that can be used to locate the people in water. Sadly, they are still relying on the divers to locate the bodies, which is very time consuming and cumbersome process," he said.
Rao, who is a dam engineer in the Andhra Pradesh government, said the rescue workers of National Disaster Response Force (NDRF) and the army should use high-tech thermal imaging equipment.
More than 60 engineering students and faculty members were on an excursion to Manali.
Some of them were getting themselves photographed on the bank of the river in Thalaut area near Hanogi Mata temple near Mandi town when the sudden rush of water washed them away.
The river level suddenly increased due to release of water from the Larji hydropower project's dam without warning, eye witnesses said.
Anxious parents of the missing students reached here Monday night through a special flight.
Most of the parents, who also interacted with NDRF, sought that the 15-km river stretch between the accident spot and the Pandoh dam should be dried up to locate the bodies.
Official sources said the NDRF officials tried to convince them that the bodies might have got stuck in the mud or boulders on the bed of the river.
"Moreover, it's virtually impossible to stop the flow of the river. As the glaciers in the river catchment are thawing with the rise in temperature, the water and its speed is increasing. Also the terrain is such that the river flows at a faster speed," an official told the parents.
Rescue workers of NDRF and the army Tuesday started the search operation. So far bodies of five students have been traced.
Their chances of survival were bleak, officials said.
"We have again started the search operation this (Tuesday) morning to locate the missing people," Jaideep Singh, NDRF commanding officer, told IANS.
Singh said a team of 84 people, comprising 10 underwater divers, have been deployed.
Official sources said an army team also started the search operation Tuesday.
The Himachal Pradesh High Court Monday said it was not only a case of callousness but a grave negligence.
"It's a sad tale by reason of the fact that sheer fun of the young students turned out to be fatal as a consequence of utter and callous negligence of the power project authorities," Justice Tarlok Singh Chauhan said, taking suo moto notice of the incident.
He directed the state government to file a status report on the incident by June 16.
The accident spot is located some 200 km from state capital Shimla and on the border of Kullu and Mandi districts.