Leading terrorist groups operating in Jammu and Kashmir denied on Wednesday any role in the bomb blasts in Mumbai and described the attacks as "barbaric" or "outrageous".
The security sources were quoted as naming Pakistan-based Lashkar-e-Taiba (LeT) as the prime suspect for the seven bomb blasts on Mumbai's rail network on Tuesday that killed at least 183 people and wounded close to 700.
But Lashkar denied any role.
"These are inhuman and barbaric acts. Islam does not permit the killing of innocent people," a man who identified himself as "Doctor Ghaznavi", spokesman of the Lashkar-e-Taiba said.
"Blaming LeT for such inhuman acts is an attempt by the Indian security agencies to defame Kashmiri mujahideens," he said in telephone calls made to newspaper offices in Srinagar.
Another terrorist group, Hizb-ul-Mujahideen, denounced the bomb attacks as "outrageous", saying it abhorred the killing of civilians.
"Attacks on civilians are not part of our manifesto. We never carried out such attacks nor will allow anyone to do so," the group's spokesman, Ehsan Elahi, said in Islamabad.
The Mumbai blasts took place hours after suspected Islamist terrorist killed eight people, seven of them tourists, in five grenade attacks in Srinagar.
Police in J&K accuse Lashkar of being behind the attacks and say they have already arrested one grenade thrower from the group.