Dibrugarh, Aug. 31: Security agencies in the state have shed more light on Ulfa’s use of Bangladeshi territory for its operations in Assam with police tracking down mobile phone numbers of the neighbouring country belonging to two of the outfit’s leaders for extortion in Sivasagar district.

The two Ulfa leaders made the phone calls to businessmen in the district, demanding money, using SIM cards of Bangladesh with the two numbers — 880173217334 and 8801816480754.

The two have been identified as self-styled captain Apurba Baruah alias Bhaity Baruah and self-styled sergeant Niren Sarma.

The police said at least 20 people — majority of them tea garden managers and established businessmen — received extortion demands over phone from a couple of Ulfa leaders.

The extortion demands ranged from Rs 20 lakh to Rs 40 lakh.

“All those who informed us about the extortion demands had one thing in common — the numbers from which they received the calls were from Bangladesh. After investigation, we have been able to find out that these numbers have international roaming facilities and Ulfa leaders were using the phones from either Bangladesh or their camps in the border areas of Nagaland and Myanmar,” Sivasagar superintendent of police Shyamal Saikia said.

“We have already started taking necessary steps in this regard. However, I would not like to divulge details at this juncture since it might hamper further investigation,” he said.

As a follow-up to the phone calls from the two Ulfa leaders, people had also received extortion notes signed by the self-styled commanding officer of the 28 battalion, Bijoy Chinese alias Bijoy Das, and also his deputy, operations commander Michael Deka Phukon.

Some garden managers and businessmen had sought help from the Sivasagar SP urging him to ensure adequate security for them.

“Adequate measures are being taken from our side. Actually, Ulfa had suffered severe blows in Sivasagar district during the past couple of years, which is why it is desperate to stage a comeback, which we will not allow in any case,” Saikia added.

According to official figures, from January 2007 till date, over 30 Ulfa cadres had been killed in various encounters with security forces in the district. During the period, over 55 cadres of the outfit had been arrested, of whom, around 20 are facing charges under the National Security Act (NSA).

Police sources said Ulfa was trying hard to build up its replenished coffers in Upper Assam and had therefore started making extortion calls. The outfit had been at the receiving end since the unilateral ceasefire declared by two of the prominent companies — Alpha and Charlie — of the 28 battalion on June 24 last year, they said.