Gilani's remarks came a day after the government confirmed that the lone surviving gunman from the attack that killed 179 people in India's financial capital was a Pakistani.

The Prime Minister sacked his national security adviser on Thursday for disclosing this before consulting him.

"The situation on our eastern border has once again become very fragile," Gilani told a seminar in Islamabad.

While tensions have run high between the nuclear-armed neighbours, there has been no sign of a troop build-up by either side, and analysts say chances of India resorting to military action have receded.

Pakistani officials have warned that if there was any risk of a confrontation with India it would switch forces from the western border with Afghanistan, where they are fighting pro-Taliban and al Qaeda militants.

Any such action would undermine incoming US president Barack Obama's plan to almost double the number of US troops in Afghanistan as part of a surge strategy to quell the Taliban insurgency.

Dell Dailey, the State Department's counter terrorism coordinator, told reporters in Washington on Tuesday that the United States had not seen any move of Pakistanis forces from western border regions to the east "in any degree that's measurable".

He said Pakistan moved troops to the eastern border in 2002, when it went to the brink of a fourth war with India.

"We do not want that to happen again and we'll do as much as we can to prevent it," Dailey said.