A migrant labourer believed to be from Bengal died and nine other workers, including four from the eastern state, are trapped under rubble after an under-construction mountain tunnel collapsed on Thursday night on the Jammu-Srinagar national highway in Ramban, with a landslide putting the brakes on a painstaking rescue operation on Friday afternoon.

An official said the rescue work that had already stretched to 17 hours had to be suspended in the evening following the landslide and a fresh assessment was being made after consultations with experts on how to resume the operation.

The under-construction tunnel caved in around 10.15pm on Thursday but the rescue operation had to wait till midnight as stones and debris from the portion of the mountain through which the tunnel was being drilled continued to come off and could have harmed the rescuers.

Three injured labourers who were not trapped inside the caved-in portion were rescued.

An official said the construction company had told them that 10 men working on night shift were trapped in the debris. The body of one of them was recovered on Friday. He is from Bengal but his identity has not been revealed yet.

Sources said the tunnel, an offshoot of the main tunnel, was a cramped space and offered little space for those trapped to wriggle to a safer place.

“It is an Adit tunnel to the main T4 tunnel and we had barely drilled three metres when it caved in. If it was deep enough, the labourers could have taken shelter inside. But they had no space there. They are under mounds of rubble but we are hoping for a miracle,” an official said.

Adit tunnels are used as escape routes during emergencies and to replenish supplies and act as ventilators.

Dhir Singh, who drives an earthmover, said he and several other rescuers had a narrow escape when the landslide hit the area at 4.45pm on Friday. He said it would have taken another half an hour to reach those trapped and so the rescue bid was suspended.

Videos showed big boulders raining down on the accident site in the afternoon, forcing panic-stricken people to run for safety.

Earlier, a big earthmover that was impeding the rescue had to be pushed down a 300m-deep gorge to remove the bottleneck.

Ramban district commissioner Musarrat Islam said the accident site near Khooni Nallah had a weak strata, necessitating the use of minimum machinery and slow movements to avoid vibrations.

Musarrat said of the 10 men who got trapped, five are from Bengal, two from Nepal, one from Assam and two are locals.

“There were 10 missing persons and (of them) we have been able to recover one body, a labourer reportedly from Bengal,” the deputy commissioner told reporters at the accident site.

A government spokesman said lieutenant governor Manoj Sinha was monitoring the rescue operation.

Official have identified the missing as Jadav Roy, 23, Gautam Roy, 22, Sudhir Roy, 31, Dipak Roy, 33, and Parimal Roy, 38, from Bengal, Shiva Chowhan, 26, from Assam, Nawaraj Chowdhury, 26, and Khushi Ram, 25, from Nepal and Muzaffar, 38, and Ishrat, 30, from Jammu and Kashmir.