The accident took place late Monday, when the truck ploughed into the Maruti car in Ghatampur area.
"By the time we could reach the spot, all the four men succumbed to burns. We are yet to identify the victims as their bodies have been charred beyond recognition," police Inspector A.N. Rai told reporters in Kanpur, some 80-km from Lucknow.
Following the collision, the liquefied petroleum gas (LPG) cylinder in the car blew up and the flames engulfed the car, he said.
The truck driver is absconding.
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