A massive search operation resumed on Sunday by using a high-tech device that can scan the riverbed full of silt and boulders to locate bodies of 16 engineering students and a tour operator from Hyderabad who were washed away in the Beas river near this town last week.

"We deployed side scan sonar to capture pictures of the riverbed to locate the bodies. In this operation, we are using this equipment for the first time," Jaideep Singh, commanding officer of the National Disaster Response Force (NDRF), told IANS.

In the first four days of the operation, eight bodies were recovered. However, no body was traced in the past two days.

Most of the bodies recovered, say officials, were either trapped under the rocks or buried in the riverbed silt within a three-km radius of the accident spot Thalaut on the Chandigarh-Manali national highway 21.

"We can now go for the possibility to open the floodgates of the Pandoh dam so that the water level in the reservoir is reduced drastically and the bodies, if trapped in boulders or stuck in the slit, surface," Telangana Home Minister Nayani Narasimha Reddy, who is camping in Mandi, told IANS.

He said some parents of the missing students have apprehensions that the bodies might washed away further if the water is allowed to go downstream.

"But any decision in this regard will be taken with the consent of the parents," he added.

The district administration on Saturday sought the consent of about 25 parents and family members of the missing students, who are camping in Mnadi since Monday, to allow the administration to open the floodgates of the dam so that the bodies, if stuck in the reservoir, could be fished out.

Official sources said the depth of the reservoir is between 30 and 50 feet deep.

"We can easily trace the bodies, if they are further washed away with the release of water from the dam, as the river stretch is narrow downwards," Deputy Commissioner Devesh Kumar, who is coordinating the search operation, said.

The water level in the three-km river stretch near the accident spot was lowered on Saturday for the first time but there was no major achievement.

In a massive operation, over 550 rescue workers, comprising around 50 divers of the NDRF, the army, the navy and the ITBP, are involved in the joint search operation, focusing on the 15-km-long downstream stretch of the river from the Larji hydropower project dam to the Pandoh dam.

The tragedy occurred when a group of students from the VNR Vignana Jyothi Institute of Engineering and Technology were swept away last Sunday when water was released into the river without warning from a nearby 126 MW Larji hydropower project. The students were on an excursion to Manali.

Police have registered a case against the Larji hydropower project authorities for causing death by negligence and endangering the life of people.

(NDTV)