Pakistan wants India tension defused after attack

"It is in Pakistan's interests and in India's interests to defuse the situation. Lowering of tension is essential," he said.

Zardari, battling Islamic radicals at home, told Indian television he would cooperate in the investigation.

"If any evidence comes of any individual or group in any part of my country, I shall take the swiftest of action in the light of evidence and in front of the world," he told CNN-IBN.

Pakistan is seen as vital to U.S.-led effort to defeat al Qaeda and bring stability to its western neighbour, Afghanistan, but a senior security official said war on terror would not be a priority if tension escalated on the eastern border, with India.

"If something happens on that front, the war on terror won't be our priority," said the official, who declined to be identified. "We'll take out everything from the western border."

The security official also denied the involvement of any Pakistani institution in the Mumbai attack and said the next day or two would be crucial in assessing India's response.

SPY CHIEF NOT GOING

Qureshi, who was in India on a scheduled visit to boost ties when the Mumbai assault began, echoed that, saying terrorism was a common enemy and India should not jump to conclusions.