About 100 people have been arrested for their suspected links to the unprecedented bombings in Bangladesh, which left two people dead and 140 injured, the police said on Friday.
Nine of them, including two who confessed about their involvement in Wednesday's bombings, were being questioned by detectives in the capital Dhaka, they said.
Sixty-three enquiry committees, which had been set up were working round-the-clock to find clues to the near simultaneous explosions of over 400 crude bombs across the country.
Police said 63 of Bangladesh's 64 districts were hit by the bombings, the first such attack in this politically volatile south Asian country.
Police sources said that at this stage of the probe everything was being looked at and nothing, including involvement of the Jamiat-ul-Mujahideen Bangladesh, was being ruled out.
The Jamiat-ul Mujahideen, leaflets under whose name were found at the blasts site, wants the establishment of Islamic rule and has warned of serious action if its demand is not met.
The activities of Jamiat-ul Mujahideen came to light in 2002 when its 'commander' and eight others were arrested from Dinajpur distribting leaflets carrying Osama bin Laden's call for 'jihad' as well as cassettes containing speeches of the Al Qaeda leader.
Folowing this, its alleged involvement was found in several cases of bombings, arson and murderous attacks, mostly against the Opposition Awami League, leftist organisations, cultural activists and non governmental organisations like the Bangladesh Rural Advancement Commitee that were conidered 'un-Islamic' by the outfit.
Sources said the organisation, which was banned by the Bangladesh government in February 2003, has a network in eight distrits of Rangpur and 39 madrassas and is supported by a prominent Jamaat-e-Islami leader from Dinajpur.
The government had banned another fundamentalist outfit Jagrata Muslim Janata Bangladesh in February 2005. Prime Minister Khaleda is cutting short her visit to China following the bombings.
Two of the arrested, who have confessed to their involvement, have told police that they would become martyrs if killed in the operation, according to the Bengali-language Daily Samakal newspaper.
They claimed they carried out the attack for the sake of Islam.