Prime Minister Manmohan Singh [Images] on Saturday asked Pakistan to come out with a 'full and complete disclosure about the 26/11 terror attack on Mumbai [Images] without attempts at 'denial, diversion or obfuscation'.

In a blunt message, he said Pakistan should act against the Lashkar-e-Tayiba [Images] and other terrorist groups and their sponsors operating from that country in its own interest.

In its first formal response to India with regard to the Mumbai attacks, Pakistan had on Friday said it had initiated a 'series of actions' in connection with the probe into the terror strikes and claimed to have shut down five training camps of the banned Jamaat-ud-Dawa and arrested several LeT leaders.

The Prime Minister said the barbaric attack was not without deeper intent and was meant to be an attack on "our very concept of nationhood".

"Mumbai is the best-known symbol of free, pluralistic, dynamic and cosmopolitan India. That is precisely why the terrorists chose to attack it," he said.

But the terrorists should know that the civilised world is against them and that no country can or will tolerate their onslaught, the prime minister said.

India has shared the evidence that it has gathered so far on the incidents with Pakistan and others. "Pakistan has admitted that the arrested terrorist (Ajmal Amir Kasab [Images]) is their national".

"We expect Pakistan to take all the consequent next steps against all those who have planned, organised and executed these horrific crimes," he said.

Noting that "the Pakistan government has announced that the results of their investigations will be made public in a few days," 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".

Asking Pakistan to discharge its obligations under international instruments and honour the bilateral commitments it has given to India at the highest level, he said it should ensure that nothing like Mumbai, or the attack on the Indian embassy in Kabul, ever happens again.

Seeking the assistance of the international community, the Prime Minister said it should use its full weight to see that the investigations are pursued vigorously and brought to a speedy and logical conclusion and that terror groups operating from Pakistan are 'completely shut down'.

"If Pakistan is sincere in its words, it should show through its actions that it will not tolerate these assaults on civilised norms of behaviour," he said.

Singh admitted that at the end of the day, this is a problem that "we will have to tackle ourselves with our own sources and our own determination. We need to strengthen our own ability to deal with such attacks and our intelligence capability to anticipate them".

The prime minister recalled that he was a resident of Mumbai for "three happy years and I feel keenly the pain and anger of the city. To the people of Mumbai, I can only say that we will take every effort to ensure that their city does not suffer any such attack in the future".

Singh said he particularly wished to salute the bravery and sacrifice of the men of the Mumbai police and the National Security Guard, who laid down their lives fighting the terrorists.

Amidst heavy security arrangements, the PM also visited the Trident-Oberoi hotel for the first time after the November 26 terror attacks.

Singh was at the hotel, which was seized by terrorists during the strikes, for an award function. The whole area around the hotel was cordoned off as part of massive security arrangements.

"Every step was taken to ensure that there was no untoward incident. The venue and the area around it were combed by security agencies and a clearance was given for the PM's visit," Joint Commissioner of Police (Law and Order) K L Prasad said.

"All the routine security checks inside the hotel were carried out by the hotel security staff. Mumbai police also conducted security checks inside and outside the hotel premises," hotel sources said.

The ceremony was originally scheduled for November 28 at the same hotel and the venue was cleared by security agencies.

"Although I visited the city along with Congress president Sonia Gandhi [Images], immediately after the event, I had no opportunity to speak in public on that occasion. I would, therefore, like to use this opportunity to say a few words on that painful subject," Dr Singh said.