The accident took place near Jasurgarh Chamba-Tissa road, about 400 km from here, police said.
The deceased have been identified as Satish Kumar (40), Ajay Kumar (45) and driver Sanjay Kumar (36), all residents of Bhalai village in Chamba district while the injured Sushil Kumar (62) hails from Kandi village.
The occupants of the ill-fated vehicles were returning from Chanjo.
Hearing the sound of the falling vehicle, the local villagers reached the spot along with rescue teams of police and local administration and recovered the bodies which were later taken for post mortem to a nearby village police said.
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