New Delhi - Evidence gathered by Indian security agencies established conclusively that militants based in neighbouring Pakistan were involved in the Mumbai terrorist attack and hard decisions would be taken to protect the country and its people, Indian Home Minister P Chidambaram said in parliament Thursday.

"The finger of suspicion points to the territory of our neighbour, Pakistan," Chidambaram said while making a statement on the November 26 terrorist attack that left at least 170 dead in India's financial capital.

"We will strain every nerve to defend our borders ... Given the nature of the threats, we cannot go back to business as usual. Hard decisions will be taken to protect the country and its people," Chidambaram said.

He also gave details of how the attack took place and said that there had been lapses in intelligence and security and these were being reviewed and steps taken to rectify the situation.

"South Asia is the eye of the storm of terrorism," Chidambaram said, adding that India had told the United Nations that it would act to safeguard its people.

If South Asia was the eye of the terrorism storm, Pakistan was the epicentre, leader of the opposition LK Advani said in his address.

His Bharatiya Janata Party and the main opposition alliance would support the government in its "hard decisions," Advani added.

Describing the Mumbai attacks as a "terror war," Advani said India should not be fooled by the cosmetic steps Pakistan seemed to be taking against terrorist elements based in that country. (dpa)