Four trucks were set ablaze on Sunday by an extremist outfit, People's Liberation Front of India (PLFI) at Aara Ghati in Jharkhand's Khunti district.
The trucks carrying coal tar and iron equipment were stopped by PLFI activists and set it on fire, Superintendent of Police, Jatin Narwal said.
The police doused the flames, he said adding that the police were searching for the drivers of the vehicles, who fled the scene after the incident.
The trucks were going to Khunti from Tamar, he said adding that a combing operation was launched to flush out the ultras.
The district police and para-military personnel were already on a long-range patrolling in the stronghold areas of another Naxal group "Jharkhand Liberation Tigers" in the district, he said.