Police yesterday blamed the Pakistani Taliban for attacks that killed 93 people at two mosques belonging to a minority sect.
They said the militants involved had trained in an Afghan border region where the US wants Islamabad to mount an army operation.
The attacks against the Ahmadi community occurred minutes apart on Friday in two neighbourhoods in the eastern city of Lahore.
Two teams of gunmen, including some in suicide vests, stormed the mosques and sprayed bullets at worshippers while holding off police.
At least two of the seven attackers were captured, while some died in the stand-off.
Local TV channels had been reporting that the Pakistani Taliban, or one of their affiliates, had claimed responsibility for the attack.
Senior police officer Akram Naeem, in Lahore, said their interrogation of one of the arrested suspects revealed that the gunmen were involved with the Pakistani Taliban, which has staged attacks across the country for years. The 17-year-old suspect told police that the men had trained in the North Waziristan tribal region.
"Our initial investigation has found that they all belong to Tehrik-e-Taliban Pakistan, or Pakistani Taliban movement," Mr Naeem said.
He said the suspect, "Abdullah alias Mohammad, was given terrorism training in Miran Shah" - the main city in the North Waziristan tribal region.