In a speech delivered in Washington on Thursday, President Barack Obama revealed clearer guidelines for America's use of drone strikes on citizens abroad.

"...This new technology raises profound questions about who is targeted, and why; about civilian casualties, and the risk of creating new enemies; about the legality of such strikes under U.S. and international law; about accountability and morality," the president said.

"And yet as our fight enters a new phase, America's legitimate claim of self-defense cannot be the end of the discussion. To say a military tactic is legal, or even effective, is not to say it is wise or moral in every instance. For the same human progress that gives us the technology to strike half a world away also demands the discipline to constrain that power - or risk abusing it."

The commander in chief continued, going into further detail about how, when and why the U.S. has authority to use drones in the fight against terror.

"...Over the last four years, my Administration has worked vigorously to establish a framework that governs our use of force against terrorists - insisting upon clear guidelines, oversight and accountability that is now codified in Presidential Policy Guidance that I signed yesterday," he said.

"America does not take strikes when we have the ability to capture individual terrorists. Our preference is always to detain, interrogate, and prosecute them. America cannot take strikes wherever we choose. Our actions are bound by consultations with partners, and respect for state sovereignty. America does not take strikes to punish individuals. We act against terrorists who pose a continuing and imminent threat to the American people, and when there are no other governments capable of effectively addressing the threat."

President Obama acknowledged that strikes have, in the past, resulted in civilian casualties, calling it a "risk that exists in all wars."

"For the families of those civilians, no words or legal construct can justify their loss. For me, and those in my chain of command, these deaths will haunt us as long as we live, just as we are haunted by the civilian casualties that have occurred through conventional fighting in Afghanistan and Iraq."