Suspected militants from anti-talks faction of Dima Halam Daogah (Jewel Garlosa) or Black Widows gunned down  four workers of a cement plant owned by Vinay Cement at Umranghsu in North Cachar Hill district of Assam on Tuesday.

The police informed that ultras fired upon a vehicle carrying Vinay Cement workers from the cement plant at Umrangshu to a lime stone mine located about five km away killing four persons on the spot and injuring two others.

The militants also burnt down the vehicle. The workers were going to collect limestone from the mine.

The incident created panic among employees working in the Vinay Cement plant in Umrangshu. A team of police and paramilitary force personnel had rushed to the incident site after the killings.

The Black Widow ultras have been on a rampage in North Cachar Hills for quite some time taking advantage of the forested terrain.

The Black Widow ultras have earned notoriety for serving extortion notices to all and sundry in the hill district, especially industrial units.

A central sector power generation corporation, the North Eastern Electric Power Corporation (NEEPCO) has found it difficult to run its 275-MW Kopili Hydel Power Project in Umrangshu due to constant threat from the Black Widow ultras.

The militants group attacked employees and security staff of Umrangshu plant of Kopili Power Projects twice so far this year since January 14 last killing total nine persons, including security personnel and a child.

The Black Widow had served Rs 2 crore extortion demand on the power corporation.

Meanwhile, life was paralyzed in Assam on Tuesday due to a 12-hour Assam bandh called by the banned United Liberation Front of Assam.

All offices, banks and other financial institutions, business organizations, educational institutions in the state remained closed during the bandh period. However, the state secretariat in Dispur capital complex functioned normally.