Investigating agencies on Friday questioned over 20 persons as they probed a possible HuJI-ULFA link behind the deadly serial blasts in Assam which claimed 77 lives, while curfew was clamped in worst-hit Ganeshguri here after protesters went on rampage.
The scale and planning behind the blasts have led the police to suspect local militants joining hands with terrorist outfits to carry out the coordinated strikes.
A team of NSG experts from New Delhi visited the blast sites at Ganeshguri, the deputy commissioner's office and Fancy Bazaar here to make an on-the-spot assessment of yesterday's terror strikes that left over 450 wounded.
"We are not taking seriously the denial by the United Liberation Front of Assam (ULFA-of being responsible for the blasts) because on earlier occasions also they have done so", a top Assam police official said.
The ULFA cadres are being trained by the Jehadi militants and there is definitely a link between the two which is being investigated, he said.
While suspecting the hand of the Bangladesh-based Harkat-ul Jehad-e-Islami (HuJI) outfit, police claimed to have got clues that the blasts were carried out by people having local links. Thus the ULFA angle has come in, the official said.
Schools and educational institutions remained closed in Guwahati while a total shut-down was observed in Kokrajhar following a bandh call by VHP and BJP.
Curfew was clamped in Ganeshguri, adjacent to capital complex at Dispur, rocked by three blasts, after protesters turned violent forcing police to fire in the air.
The protesters gathered near a flyover - a few meters from the blast site, shouting slogans against the government's alleged failure to provide security to the common people.
Deputy Commissioner Prateek Hajela said the protesters, turned violent and attacked the security personnel deployed in the area.
The police first resorted to lathi-charge to disperse the protesters but later fired in the air, Hajela said.
Ganeshguri had witnessed protests soon after the blasts yesterday with the mob torching a police vehicle, a fire tender and two ambulances.
BJP leader LK Advani visited the blast site near the Deputy Commissioner's office where he faced a group of angry lawyers who shouted slogans 'Advani go back'.
He also visited the Guwahati Medical College Hospital and met the injured in the blast.
All examinations scheduled under the Gauhati University and State Education Board of Assam (SEBA) has been cancelled till further directive.
Attendance in the offices was thin and in many areas shops and business establishments, particularly those in and around the blast sites, remained closed. Frequency of public transport operations dropped significantly in the morning hours.
Opposition Asom Gana Parishad observed a 'Black Day' on Friday with its leaders and cadres sporting black badges.
Lawyers of both High Court and Sessions Court in Guwahati abstained from work and held protests outside the court premises.