Preliminary investigation into Thursday's serial blasts in Assam indicated use of highly damaging PE-3 explosives in RDX base even as the Assam police pointed an accusing finger at Jehadi groups for the serial terror attack.

Police sources informed that PE-3 explosive was used for the first time in the Northeast. Such explosives cause serious burn injuries to the blast victims as was evident in Thursday's blasts.

Assam police intelligence chief K N Sharma told media-persons in Guwahati that it would be too early to pinpoint any jehadi group behind the blasts as of now when the investigation was a preliminary stage. He said jehadi groups tended to work in coordination and carry out tasks assigned to them by anti-Indian forces.

Chief Minister Tarun Gogoi did not blame the failure of  intelligence agencies for the blasts. He said that there were intelligence inputs that terrorists might strike in the state around Durga Puja and Diwali, but terror acts of such intensity were not anticipated.