According to sources, Indian government has proof of the involvement of Pakistan's ISI in the terror attacks in Mumbai. Sources in Delhi said that the names of trainers and places where scrupulous training took place of the terrorists that killed 183 people during a 60-hour siege Mumbai are known to the government.

U. S. has a lot more evidence, some of which it has shared with India.

US Joint Chief of Staff chairman Mike Mullen, who was in New Delhi on Thursday, has ostensibly told his Pakistani counterparts a day earlier that Washington had enough evidence to show a Pakistani hand in the Mumbai attack. They also said it was unlikely that the Pakistani army did not have information about the Mumbai operation since it controls the ISI.

Yet, Pakistani President Asif Ali Zardari maintained that Islamabad would "take strong action against any Pakistani elements found involved in the attack" and "Pakistan is determined to ensure that its territory is not used for any act of terrorism."

In his meeting with US secretary of state Condoleeza Rice in Islamabad on Thursday, Zardari told Rice he had asked India to see this as a chance to work together rather than be at loggerheads, saying: "I intend to do everything in my power."