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.