The mishap occurred at around 12.30 PM on Rupa Kalaktang road when the pick-up vehicle was on its way to Betchelling village, Power Minister T N Thongdok, who represents the area, said over phone.
Thongdok has rushed to the spot to take stock of the situation.
"I am in touch with administration and have apprised Chief Minister Kalikho Pul who has assured all possible relief. ... Let us pray for peace of all departed souls. Condolence to families of the victims," Thongdok said.