President Asif Ali Zardari said on Friday that Pakistan is awaiting "concrete proof" on suspicions that a Pakistan-based militant group was behind Mumbai attacks. Meanwhile recently discovered evidence indicate that the Mumbai attacks were controlled from at least two Pakistani cities by top leaders of the Pakistan-based terror group LeT, prime suspect in last week's attacks.

"Pakistan is currently doing its own internal investigation and is waiting for concrete proof to be handed over to us," Zardari told reporters after a trilateral meeting with the leaders of Turkey and Afghanistan.

Indian and American intelligence officials have already identified a Lashkar operative, Yusuf Muzammil, as a mastermind of the attacks.

According to the investigators, Muzammil apparently served as a control officer in Lahore, Lakhvi, his boss and the operational commander of Lashkar, worked from Karachi.

Both these men seemed to have been in contact with their charges, the militants, as they sailed to India from Karachi and continued guiding the attacks even as they unfolded, giving directions for the the assaults and perhaps even providing information about the police and military reaction in India.