WASHINGTON (INP) - US National Security Adviser Tom Donilon has said that al-Qaeda leader Osama bin Laden 'had some sort of support mechanism while functioning out of Abbottabad for six years. Osama bin Laden, who had evaded capture for a decade, was killed on May 2 in a top-secret raid involving a small team of US Special Forces on his Abbottabad hideout. In an interview to CNN, Donilon said he had not seen evidence that Pakistani 'leadership elements had knowledge of Osamas presence in Pakistan. 'I dont have any evidence that has been shown to me which indicate that the Pakistani leadership and the political and the military, the intelligence services, had foreknowledge here, Donilon said in the interview. 'But the fact is that he functioned there for an extended period of time, and that raises a lot of questions. And those questions are being asked in Pakistan, he added. The US Congress has been calling for more information on whether the Pakistani military, government or intelligence services aided Osama while he was in Abbottabad , about 35 miles from the countrys capital of Islamabad. The issue has contributed to tensions in the already-strained relations between the US and Pakistan. US intelligence agencies are currently examining computer equipment found at Osamas lair for leads on additional al Qaeda figures and their plans. Citing a Central Intelligence Agency (CIA) assessment, Donilon had said in May that the information cache is about the size of a small college library. Meanwhile, US Special Envoy for Pakistan and Afghanistan Marc Grossman has said that Pakistan is beset with two major challenges such as terrorism and weak economy for which both the US and Pakistan would have to cooperate with each other. He said the terrorists have martyred over 19,000 Pakistanis for which Pakistan deserves high regard and respect, he said while addressing the annual dinner of American doctors organisation 'APNA here. He said the intelligence, military and political leaderships have useful talks in Afghanistan and the delegation for July 5 dialogue would discuss several matters in detail.