The president was asked about the debate over the deadly tactic, a backbone of the US campaign against Al Qaeda, and whether the Constitution allows the use of drones against Americans who have turned against their country.
"It is not sufficient for citizens to just take my word for it that we are doing the right thing," Obama told an online forum sponsored by Google.
The president, who has said he is working with Congress to provide more oversight of the clandestine drone war against Al Qaeda, was also asked what was to stop the US government from using unmanned aerial vehicles at home.
"There has never been a drone used on an American citizen on American soil," Obama said in the Google Plus "Fireside Hangout."
"The rules outside the United States are going to be different than the rules inside of the United States in part because our capacity, for example, to capture terrorists in the United States is going to be very different than in the foothills or mountains of Afghanistan or Pakistan.
Debate about the use of drones has slowly been mounting following the September 2011 killing in Yemen of cleric Anwar al-Awlaki, a senior Al-Qaeda operative who was an American citizen.
The president said that he was working with Congress to ensure that the public was also able to understand the constraints and legal rationales of the US drone war.
"I am not somebody who believes that the president has the authority to do whatever he wants, or whatever she wants, whenever they want, just under the guise of counter terrorism," he added.
"There have to be checks and balances on it."
Some observers, including prominent senators, are considering whether a special court should monitor the secret drone war.
Missiles fired from unmanned aircraft have become the Obama administration's weapons of choice in its war against Al Qaeda.
The administration's legal rationale for the targeted killings was leaked to the media ahead of Senate hearings last week on the nomination of Obama's top counterterrorism adviser John Brennan to head the CIA.
The guidelines allow the use of drone strikes against US citizens suspected of being senior Al Qaeda operatives, even if there is no evidence they are actively plotting an attack.
Some administration critics have questioned the legality of drone strikes against US citizens, while others fear that raining death from the skies may do more harm than good in increasing anti-US sentiment.