Central intelligence agencies suspect Pakistan-based Lashkar-e-Tayiba's hand in Monday's twin blasts in Mumbai, which killed 45 people and left over 150 injured.
Mumbai blasts: The complete coverage
Official sources said preliminary investigations have indicated the blasts were carried out by some Students Islamic Movement of India cadres, who had received training in handling of explosives in the Gulf.
The Mumbai police, under tremendous pressure because of a series of blasts in the capital recently, agree that Monday's twin blasts were the handiwork of an organised terrorist network, but have not named any group yet.
Sources said there were indications that underworld don Dawood Ibrahim's gang could have provided logistical support for the blasts.
Some Dawood gang members, deported from Dubai to Mumbai, have disclosed that Lashkar is imparting training to banned SIMI members to avenge the Gujarat riots.
Meanwhile, the Mumbai police has despatched crack teams to Pune and Aurangabad to follow some early leads.
Sources said investigations into the blasts at Mumbai Central on December 6 last year and Mulund on March 13 this year have revealed that the accused had received training in Kondva forest area of Pune.
Saquib Nachan, considered to be the ring leader of terrorist activity in Mumbai, is alleged to have organised their stay and other facilities in Pune.
The driver of the taxi, in which explosives were planted at the Gateway of India, has been picked up for interrogation, Sharma told reporters.