Naxals have hijacked a truck carrying a whopping 16.5 tonnes of high-grade ammonium nitrate explosive which was on its way here from Vishakapatnam in Andhra Pradesh.

Police have launched an operation to track the explosive which was looted yesterday by the Maoists.

Official sources said the truck carrying the large quantity of ammonium nitrate, which is used as high nitrogen fertiliser as well as for making explosives, was hijacked by the Maoists in Bastar region of the state, an area hit by Left-wing extremists.

They said the truck was on its way to Raipur from Vishakapatnam to deliver the consignment to a factory. The route through Bastar is the shortest one to reach Raipur from Vishakapatnam. The truck was not accompanied by any security guards.

The incident came to light when the truck driver was released last night, Bastar SP P Sundarraj said.

After questioning the driver, a search was immediately launched for the explosives, but no headway has been made so far, the police officer said.

Following the hijack, a high alert has been sounded in the state.

Ammonium Nitrate is used by Naxals for making improvised explosive devices which have claimed the lives of large number of security personnel.

The ultras had looted a detonator-laden truck in the same area a few months ago. The detonators are yet to be traced.