At least 18 persons were killed after a truck fell off a mountain road and plunged into a gorge near Metengliang in Arunachal Pradesh’s Anjaw district, The New Indian Express reported on Thursday.

The accident had taken place on the night of December 8. However, it came to light only two days later, when an injured survivor climbed out of the ravine and alerted the authorities, The Indian Express reported.

The truck carrying 22 persons had left from Assam’s Tinsukia district on December 7 for Chaglagam in Anjaw district. The passengers on board were labourers going to work on a construction site.

When the truck did not arrive at its destination on time, other workers notified the authorities.

Subsequently, the Hayuliang Police in Anjaw launched a search operation based on their complaint.

On Wednesday, the injured survivor managed to reach a General Reserve Engineer Force camp and alerted them about the mishap. He was shifted to Assam for further treatment.

Anjaw Deputy Commissioner Millo Kojin told The Indian Express that rescue operations could not begin on Wednesday due to the late hours and the difficulty of the terrain. However, a requisition was immediately sent to the National Disaster Response Force, he added.

Kojin said that personnel from the Indian Army, the police, the Border Roads Task Force and the district administration were part of the rescue.

A statement from the Ministry of Defence said that the Army launched a rescue operation based on the information received late on Wednesday, The New Indian Express reported.

“Preliminary inputs from the lone survivor, who managed to reach Chipra GREF Camp, indicate that a truck carrying 22 workers from Tinsukia fell off a cliff,” the newspaper quoted the ministry as saying.

It added: “The accident site lies in difficult terrain with limited connectivity and had not been reported by any local agency, contractor or civil representative until the survivor’s arrival.”

The ministry said that the truck was spotted on Thursday about 200 metres below the road in a re-entrant after four hours of an intensive search. The site was inaccessible and not visible from helicopters or the road due to dense tree cover and thick foliage, it added.

“Eighteen bodies have been sighted and are being retrieved using belay ropes,” the newspaper quoted the statement as saying.

The victims were identified as residents of the Gelapukhuri Tea Estate in Tinsukia district, The Indian Express reported.

Kojin said that the truck carrying the labourers was privately owned, adding that the passengers were being transported by a private contractor.

“The person who had asked the labourers to travel there has been called by police for questioning,” the newspaper quoted the deputy commissioner as saying.

On Thursday, Prime Minister Narendra Modi expressed his condolences to the families of those who were killed in the accident. He announced an ex-gratia amount of Rs 2 lakh each for the next of kin of the dead and Rs 50,000 for those injured.

Assam Chief Minister Himanta Biswa Sarma also expressed his condolences and said that the district administration in Tinsukia was in touch with the relevant authorities in Arunachal Pradesh.

“…all necessary assistance is being provided,” he said on social media. “Relief and rescue teams are prioritising locating missing or unaccounted people at the earliest. We are also ensuring that medical help is provided to those in need.”