"There may be those outside who question or challenge what we do," a resolute Obama told officials at the Office of the Director of National Intelligence as he addressed the deaths of 73-year-old American Warren Weinstein and 39-year-old Italian Giovanni Lo Porto.
"But I know what you do," he said. "We are more secure because of your service. We are more secure because of your patriotism and your professionalism."
"It's hard," Obama admitted. "We all bleed when we lose an American life. We all grieve when any innocent life is taken.
"We don't take this work lightly. And I know that each and every one of you understand the magnitude of what we do and the stakes involved.
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"These are not abstractions and we are not cavalier about what we do, and we understand the solemn responsibilities that are given to us."
"We welcome those questions and those challenges because that makes us better."
Asked if officials could be fired over the January operation, which came after hundreds of hours of surveillance, the White House said that it appeared protocols had been followed.
"Those policies and procedures include reaching a near-certainty assessment that civilians would not be harmed in the operation," said spokesman Josh Earnest.
Earnest added: "There is a rigorous process. But that rigorous process does not result in absolute certainty.
The Office of the Director of National Intelligence was created a decade ago after the September 11 attacks to pull together sometimes feuding and competitive agencies.
"It has been 10 long and challenging years, but when we look back on those 10 years the American people have been a whole lot safer," Obama said.