In an email to PTI, the Paresh Barua-led faction's publicity wing member Aranya 'Asom' said the outfit had officially taken responsibility for the blast.
It, however, regretted that innocent civilians were injured in the explosion.
"To avoid such injuries, we urge the people of Assam to maintain a considerable distance from uniformed persons in the future," the email said in a veiled threat that the outfit would continue with its subversive activities.
Chief Minister Tarun Gogoi, who visited the spot today, said 50 persons had been picked up by the police for interrogation and efforts were on to pin the insurgency group responsible for the blast.