WASHINGTON (AFP) Al-Qaeda is sure to mount an attack on the United States in the next three to six months, and will target the country until Osama bin Laden and his top deputy are 'dead or captured, the top US spy chief warned Tuesday. Asked by lawmakers about the prospects of Al-Qaeda striking over that period, US Director of National Intelligence Dennis Blair replied: The chances of an attempted attack are certain. Theyre going to try. Osamas extremist network, authors of the September 11, 2001 terrorist strikes on the United States, has 'deployed individuals to this country who 'continue to stay in touch with the group, said CIA Director Leon Panetta. Panetta said Al-Qaeda may look to use someone whose lack of previous ties to extremists gives them 'clean credentials - someone like accused Christmas Day bomber Umar Farouk Abdulmutallab. I think theyre going to be looking for other opportunities like that, said Panetta, who joined Blair and FBI director Robert Mueller before the Senate Intelligence Committee to lay out likely global threats to US interests. Panetta said he also worried about a 'lone wolf attacker, who undergoes 'self-radicalisation with no direction from Al-Qaeda and decides on his own to carry out an attack. Its the lone wolf strategy that I think that we have to pay attention to as a threat to this country, said the CIA chief. Blair told the committee that Al-Qaeda maintains its intent to attack the Homeland preferably with a large-scale operation that would cause mass casualties, harm the US economy, or both. We assess that at least until Osama bin Laden and Ayman al-Zawahiri are dead or captured, Al-Qaeda will retain its resolute intent to strike the homeland, he said. With President Barack Obamas administration under fire for its handling of Abdulmutallab, treating him as a civilian defendant and informing him of his right to remain silent, Blair declined to say whether Osama should get the same treatment if captured. Instead, Blair said he 'would very much hope that the Saudi-born extremist would be interrogated and that officials would 'squeeze him for information. But Mueller told the committee that Abdulmutallab has provided valuable intelligence and was still being questioned. Im confident that someone who left the trail that Mr Abdulmutallab did would now be found, said Blair. What I cant tell you is that, even with these improvements we would be able to catch someone who took more care.