Pakistani Interior Minister Rehman Malik told an Arab satellite TV on Monday he knew of the US raid which killed Osama bin Laden only 15 minutes after its launch but had no idea of the target.

"I was made aware of the operation 15 minutes after it started," the minister told Al-Arabiya channel in an interview, but he was not aware of the target.

Helicopter-borne US commandos carried out a raid lasting less than 40 minutes, killed bin Laden and took away his body from a mansion near a Pakistani military facility outside Islamabad on May 2.

Malik stressed there was "permanent cooperation in the security field" between Islamabad and Washington, despite US concerns about the reliability of their key ally in the "war on terror."

US President Barack Obama has pressed Pakistan to probe how bin Laden managed to live for years under the noses of its military, saying he must have had some kind of support network.

Under mounting pressure from both Washington and his own people, Pakistani Prime Minister Yousuf Raza Gilani was to brief his country’s parliament on Monday on the US operation of a week ago.

The White House is also calling on Islamabad to counter growing mistrust by allowing US investigators access to three of bin Laden’s widows who are in Pakistani custody and could have vital information on Al-Qaeda.

"We think that there had to be some sort of support network for bin Laden inside of Pakistan," Obama told the CBS television show "60 Minutes" on Sunday.

"But we don’t know who or what that support network was. We don’t know whether there might have been some people inside of government, people outside of government, and that’s something that we have to investigate and, more importantly, the Pakistani government has to investigate."

Senior US officials have said they have no proof Islamabad was aware of bin Laden’s hideout.