Kokrajhar, Sept. 25: Two NDFB (Songbijit) militants, including its self-styled army chief, were today arrested from Chirang district of Assam.

In another development, six suspected activists of Jamaat-ul-Mujahideen Bangladesh (JMB) were arrested from Chirang and Goalpara districts of lower Assam, taking the total number of arrests of JMB activists in the state to 10 since September 16.

NDFB (S) "army chief" Rabi Basumatary, alias Rongja Baja, and his personal security officer, Jwnglaw Narzary alias Jekhai, were arrested from Morabari jungle near Hakua river in a joint operation by Chirang police, the 54 Battalion of Sashastra Seema Bal and the army, said L.R. Bishnoi, the inspector-general of police of Bodoland Territorial Areas District (BTAD).

An AK-56 rifle, 170 rounds of AK ammunition, 50 rounds of Insas ammunition and four hand grenades were recovered from them, he added.

Basumatary was involved in the killing of Narayan Barman, the then in-charge of Rupsi police outpost in Kokrajhar district on September 26, 2013. Barman and his driver Madan Roy had died while constable Sajahan Miya was injured in the attack.

The development comes a few days after the security forces launched the "final push" against the NDFB (S), which was behind last year's Adivasi carnage, in the dense jungles of BTAD in lower Assam along the Indo-Bhutan border. A joint force of the army, police, SSB and the CRPF had started a "massive" operation on September 18 to apprehend the remaining 20-25 cadres of the outfit.

"Additional troops have been brought in to give a final push to the operations against the few remaining members of the outfit, including top-rung leaders like G. Bidai and his deputy K. Batha, who had masterminded the Adivasi carnage," general-officer-commanding of 4 Corps, Lt Gen. Sarath Chand, had said a few days ago. He had called upon the NDFB (S) militants to surrender.

Assam director-general of police Khagen Sarma had also said there would be no let-up in the intensity of the operations this time.

Defence spokesperson Lt Col Suneet Newton told The Telegraph in Guwahati today that the joint operation to apprehend the remaining leaders and cadres of the outfit was under way.

According to the army, in the operations launched following the Adivasi carnage, 18 NDFB (S) militants have been killed, 539 militants and their linkmen have been apprehended and 175 weapons, 180 hand grenades and seven improvised explosive devices have been recovered.

The self-styled deputy commander-in-chief of the outfit, Dwiswrang Daim-ary alias Dhananjay, was arrested from Sesapani forest in Kokrajhar district on August 29. On September 9, two top members of the outfit, including the ex-personal security officer of top NDFB (S) leader G. Bidai, Biron Narzary alias N. Bapeibai, were arrested from Chirang district.

The Centre is closely monitoring the operations, sources said.

In Chirang, four JMB activists were arrested today and two from Chirang and Goalpara districts yesterday in a joint operation by Assam police and the CRPF.

The police said four "fundamentalists" - Nur Hussain, 25, Habizur Ali, 25, Mustafa Mondal, 25, and Malek Sheikh, 34 - were arrested from Rajpara village in Chirang and four guns, including two AK-47 rifles, were recovered from them. All four are residents of Rajpara.

Yesterday, two others, Soleman Ali, 26, of No. 2 Dowkhanagar in Chirang and Mofidul Islam, 28, of Rajmita in Goalpara were arrested from Goalpara district.

The arrests follow that of three other JMB members on September 16, when the police bust a "training camp" believed to have been set up by a jihadi outfit at Daukhanagar in Chirang district.

Police sources today said interrogation of the three arrested on September 16 had revealed that they were a part of a JMB module operating in Assam. The existence of the JMB module in the state had come to light in October last year during investigations into the IED explosion in Burdwan in West Bengal. The police had then arrested 12 suspected JMB members, including a "key accused" of the blast, Sahanur Alom, from Barpeta district.

The police said the training centre was being run since September 7 under the guise of a martial arts school to escape the attention of security forces and the three apprehended were undergoing arms training along with nine others from Barpeta, Bongaigaon, Baksa, Nalbari and Kokrajhar districts. Six of the nine have been arrested since yesterday.

BTAD inspector-general of police L.R. Bishnoi said the main organiser of the training camp had been identified as Ashiq alias Bura Bhai of Howly in Barpeta district.

"We are looking for a person known as Mohafiz, who is the arms trainer," a police source said.

Sources said the case was likely to be handed over to the NIA, which was handling the Burdwan blast investigation.

Additional reporting by our Guwahati bureau