Osama had support system in Pakistan: US

Washington: Osama bin Laden "had some sort of support mechanism" while operating out of Pakistan for six years, a top White House official has said, even as he reiterated that there is no evidence so far which indicates that the top leadership in the country knew about it.

"The fact is that Osama Bin Laden operated out of Abbottabad, Pakistan for six years or so, in an operational role, leading al Qaeda, in a town 35 miles from Islamabad. It is clear that he had some sort of support mechanism there," National Security Advisor Tom Donilon told CNN's Fareed Zakaria in an interview.

"I don't think at this point we know all the elements of that support mechanism, and we're still obviously working through that," he added.

But, he said he had not seen evidence that Pakistani 'leadership elements' had knowledge of bin Laden's presence in Pakistan.

"I've not seen any evidence that the Pakistani leadership elements, neither in the army, military, the intelligence or the political leadership, had foreknowledge of Osama bin Laden's operating in Abbottabad, Pakistan," he said.

"But, the fact is that he did operate there for an extended period of time, and that raises a lot of questions, and those questions are being asked in Pakistan," Donilon said.

The National Security Advisor said the US has a tremendous amount of information that was recovered from the Abbottabad compound where bin Laden operated.

From the outset, he said, the Obama administration determined that it would launch an aggressive, focused, relentless effort on al Qaeda and associated groups to dismantle, disrupt and ultimately defeat them.

"With respect to the al Qaeda's leadership ranks, they've been decimated. We are going to continue these efforts, and these efforts are focused on al Qaeda Central and South Asia, but also focused on affiliates around the world, number one," he said.

Despite disagreement over a number of issues, Pakistan is a very important counter-terrorism partners for the US, he said.

"The Pakistanis and the United States have a complicated relationship and there are going to be frustrations, and there are going to be disagreements. We remained engaged with the Pakistanis for a number of very important reasons related to our national security and I think ultimately their security. They are very important counter-terrorism partners for the United States," Donilon said.

"They are very important partners of ours and, we will have frustrations and indeed we've obviously had an important set of conversations, difficult conversations with the Pakistanis since the raid on the Osama Bin Laden compound in Abbottabad, Pakistan. But we're committed to working through these," Donilon said.