A hardcore United Liberation Front of Asom militant was on Thursday shot dead in an encounter with the army in Dibrugarh district in Assam even as a security alert has been sounded across the state in the run up to the ULFA's Raising Day on March 16.

Rupa Moran, wanted for allegedly murdering Hindi-speaking people in Upper last week, was killed in a gun-battle after security forces, acting on a tip-off, cordoned off the area in Hatibandha village, where he was hiding, defence sources said.

The troops of the 11 Guards Regiment have also recovered a pistol and an improvised explosive device from him, they said.

A self styled corporal of the ULFA's dreaded elite strike force 28 Battalion, Moran was involved in the killing of four Hindi-speaking brick kiln workers at Udalguri tea estate in Tengakhat area last week and at Itakhuli area in 2007, bomb blasts in Doomdooma three days ago, besides large scale extortions, the sources added.

Official sources in Guwahati said the state was placed under a security blanket and all police stations alerted in view of the ULFA stepping up violence since last week to make its presence felt prior to its raising day.

Meanwhile, Dimasa militants belonging to Dima Halam Daogah (Jewel Garlosa) kidnapped five persons, including three officials of a construction company working for the National Highway Authority of India in the East-West corridor project from Langting near Haflong in North Cachar hills districts on Wednesday evening.

The police said the company officials were travelling in a vehicle to Langting from Lumding when the suspected DHD(J) or Black Widow militants waylaid them and abducted the entire team, including the driver and the personnel security officer.

The kidnapped company officials were identified as Umesh Chandra Sharma, project Manager, Jugaprasasad Deka, Deputy Project manager and Dhruvajyoti Chouhdury, Manager.

Work in the stretch of the East West Corridor passing through the hill district has been badly affected because of the threat from the Black Widow militants. The insurgency in the area has put a brake on the progress of work that is now running far behind schedule.

The army has launched a manhunt in the area to trace the abducted persons even as the  NHAI has suspended all its construction works in the area indefinitely in the wake if abduction of the officials of its contractor firm.

In the wake of continuing violence and regular attacks by the banned ULFA for the last four days, the opposition Asom Gana Parishad accused the Assam government for failing completely in maintaining law and order in the state.   

"Notwithstanding the claim of the government, the fact remains that bomb blasts are being triggered by militants almost every evening all over Assam, making a mockery of the security arrangement and counter-insurgency apparatus.  The government has virtually collapsed in the sense that it has become incapable of protecting lives and property of people against marauding insurgents," said senior AGP leader Chandra Mohan Patowary.

Additional reportage: PTI