US drone strikes detailed by adviser
30 April 2012 Last updated at 22:30 BST
President Obama's counter-terrorism adviser has given the most detailed explanation so far of America's use of drones to kill members of al-Qaeda during a speech at a Washington think tank.
John Brennan justified the use of the drones as legal, proportional and necessary.
"Individuals who are part of al-Qaeda or its associated forces are legitimate military targets," Mr Brennan said during the speech to the Woodrow Wilson International Center.