Prime Minister Manmohan Singh sought assurances that Islamabad would share the results of its probe into Indian allegations that Pakistani "official agencies" and militants based on its soil supported the attackers.
"Pakistan should act against the Lashkar-e-Taiba (LeT) and other terrorist groups and their sponsors operating from that country in its own interest," Singh told a public function in Mumbai, India's financial capital.
India says 10 LeT militants led the Novermber 26-29 siege, which left 174 people including nine of the gunmen, killed. The lone surviving attacker is in Indian custody.
Pakistan on Thursday promised to probe the Indian charges and premier Singh in his Mumbai address urged Pakistan to unveil its findings into the carnage.
"India has shared the evidence that it has gathered so far on the incidents with Pakistan and others and Pakistan has also admitted that the arrested terrorist is their national," he said.
"I urge the Pakistani authorities to come out with a full and complete disclosure of all the facts surrounding the case, without attempts at denial, diversion or obfuscation," he said in the hard-hitting speech.
India's fresh demands came a day after Pakistani leaders assured British Foreign Secretary David Miliband in Islamabad of their commitment to tackling militancy.
Singh earlier this month said that given the level of sophistication and planning involved in staging the attacks, they must have had support from some of Pakistan's "official agencies" -- a charge Islamabad has rejected.
Singh never identified the agencies. Islamabad says the attackers were "non-state actors".