An alleged drug trafficker transporting heroin and opium worth Rs 20 crore to Rajasthan was injured in police firing early on Saturday after he “snatched a revolver from a sub-inspector and opened fire” in Assam's Kokrajhar district, an officer said.

Police claimed that some unidentified people later set the truck ablaze but the drugs were shifted from the vehicle by then.

The Rajasthan-bound truck coming from Manipur was stopped at Srirampur check gate along the West Bengal-Assam inter-state boundary and 3.1kg of heroin and 85kg of opium were seized from the vehicle, the officer said.

The driver, hailing from Barmer in Rajasthan, was arrested.