Predator that beheaded al-Qa'ida
The CIA's drone attacks in Pakistan have been so successful that al-Qa'ida now has just two senior leaders in the country, US security officials believe.
If Ayman al-Zawahiri and his deputy, Abu Yahya al-Libi, are also killed, al-Qa'ida will be non-existent as an effective terrorist organisation, in a region once regarded as its greatest stronghold.
Predator drone strikes may be controversial, owing to the threat of "collateral damage" and the fact that their use by the US is perceived as an affront to Pakistan's sovereignty. But they are also highly effective.
In the past year Barack Obama's administration has presided over the assassination of Osama bin Laden and almost all his closest associates based in Pakistan, including Atiyah Abd al-Rahman, al-Qa'ida's chief of operations; Atiyah Abd al-Rahman, its deputy leader; and Abu Hafs al-Shahi, its leader in Pakistan.
Quoting unnamed intelligence sources, the Washington Post reported that the losses have forced al-Qa'ida to consider relocating. But they are yet to find a potential new stronghold that would be sufficiently safe.
As well as searching for its two remaining targets, the CIA is now largely using drones to keep an eye on lower-level al-Qa'ida operatives along with other, less influential insurgent groups that are still operating within the country's tribal region.