The mishap occurred last night when the jeep fell into the 350-meter deep gorge on Nakora-Khadar link road near Nerwa.
Five persons were killed on the spot, they said, adding as many were injured.
The injured persons were rushed to a hospital where condition of three of them was stated to be critical.
The deceased have been identified as Sita Ram, his son Pawan and grandson Rajat, Kanta Devi and Mahu Ram, all from village Khadar.
Sub-divisional Magistrate Krishan Chand has announced an immediate relief of Rs 10,000 to the next of kin of the deceased and Rs 5,000 to each injured person.
Meanwhile, three persons, who fell into the river Chandra-Bhaga while crossing a rope bridge near Trilokinath in Udaipur tribal area of Lahaul and Spiti district on Monday, are still missing.
They are feared to have been drowned in the surging waters of the river but their bodies have not been recovered, official sources said.
