Detailed investigations of possible war crimes arising from drone attacks in Pakistan and Yemen pose difficult questions for the US.
Saudi Arabia's second-in-command of al-Qaeda in the Arabian Peninsula, Said al-Shehri has been killed in a US drone attack in Yemen.
At least nine suspected militants have been killed in a US drone strike and a separate military operation in Pakistan's tribal region.
Unmanned US aircraft fired four missiles at a house in north-west Pakistan, killing 16 suspected militants, says Pakistani intelligence officials.
US use of drones has soared during Obama's time in office, with the White House authorising attacks in at least four countries.
A UN investigator has asked US President Barack Obama to justify his policy of assassinating terror suspects using drones rather than capturing them.
The US Central Intelligence Agency has suspended drone missile strikes on gatherings of low-ranking militants in Pakistan.
At least 30 militants were killed in less than 12 hours in a hail of missile strikes by suspected US drone aircraft in Pakistan's north-west region.
The United States conducted a drone attack in Somalia, apparently wounding two senior members of al-Shabaab.
Libyans prepared on Saturday to bury 11 imams killed in what Muammar Gaddafi's regime said was a Nato air strike.
Pakistan's Parliament on Saturday demanded an end to US drone strikes on its territory and called for a probe into the raid that killed Bin Laden.
A US drone missile strike on Thursday killed at least 38 suspected militants in a Pakistani region known as a haven for Taliban and al-Qaeda fighters.
The US military plans to to deploy a new drone in Afghanistan, which experts say will allow troops to monitor much larger operational theatre.
The president's backing of indiscriminate slaughter in Pakistan can only encourage new waves of militancy.
A US drone strike on an insurgent training centre in militant-riddled North Waziristan killed 15 militants amid a recent surge in the covert attacks.