Pakistan 'must have' backed terror attacks, says Singh

India's Prime Minister has raised the war of words with Pakistan by claiming its authorities "must have" had a hand in the terror attack on Mumbai that killed 172 people.

In the most outspoken comments yet from an Indian official, Manmohan Singh said the sophistication of the November attacks meant the terrorists must have had the support of some "official agencies in Pakistan".

While he stopped short of directly accusing the Pakistani government, Mr Singh's comments drew a defiant response from Pakistan. The country's Foreign Ministry accused Mr Singh of engaging in a "propaganda offensive".

On Monday, India gave Pakistani officials a dossier of evidence which it said outlined convincingly the role that Lashkar-e-Toiba militants based in Pakistan had played in plotting and carrying out the gun and bomb attacks which left parts of Mumbai under siege for more than 60 hours.

At a Delhi meeting of the chief ministers of Indian states, Mr Singh said: "Unfortunately, we cannot choose our neighbours. Countries like Pakistan have in the past encouraged and given sanctuary to terrorists and other forces who are antagonistic to India.

"There is enough evidence [in the dossier] to show that, given the sophistication and military precision of the attack, it must have had the support of some official agencies in Pakistan."

Since the attacks, India has repeatedly demanded that Pakistan do more to dismantle Lashkar-e-Toiba and prosecute its members. Pakistan has detained about 50 people linked to the group and shut down some of its facilities but India insists that it do more. Pakistan has said it can only prosecute those accused by India once it is provided with comprehensive evidence.

Mr Singh did not specify which agencies he believed had supported the attacks but his comments were taken to refer to Pakistan's controversial ISI intelligence agency.

Last summer, CIA officials flew to Pakistan to provide the government with evidence that they said pointed to the involvement of elements within the military-controlled ISI in a July bomb attack on the Indian embassy in Afghanistan that killed 58 people.

While Mr Singh's comments may have been designed to maintain political and diplomatic pressure on its neighbour, in Pakistan they were angrily denounced by the government, members of the opposition and some media.

"The policy of casting accusations without uncovering full facts and even while the investigations are still continuing is irresponsible," the Foreign Ministry said. "Vilifying Pakistan or for that matter any of its state institutions on this score is unwarranted and unacceptable. This is a sure way to close avenues of co-operation in combating this menace."