Barrack Obama: I'm Really Good at Killing People

President Barack Obama bragged to his aides that he's "really good at killing people," according to explosive claims in a new book about the 2012 presidential campaign.

The revelation comes at a time when Obama, who won the Nobel Peace Prize in 2009, has faced increasing criticism for his use of drones to target insurgents and terrorist suspects, particularly in Pakistan and Yemen.

The London-based Bureau of Investigative Journalism estimates that Obama has authorized 326 drone strikes.

Since 2004, CIA unmanned aerial vehicles have killed 2,500 to 3,600 people - including up to 950 civilians.

Barrack Obama: "I'm Really Good at Killing People"

Obama was given the Peace Prize in 2009, less than a year into his presidency, for his aspirations of nuclear disarmament

Double Down: Game Change 2012, will be released on Tuesday, but at least one early review points out the shocking detail included by authors Mark Halperin and John Heilemann.

A Washington Post report makes passing reference to the anecdote, saying that while speaking with his aides about the drone program Obama bragged that he was "really good at killing people."

The Obama Administration has not responded specifically to reports of the alleged boast from the President.

However, Obama adviser Dan Pfeiffer said that "the president is always frustrated about leaks. I haven't talked to him about this book. I haven't read it. He hasn't read it. But he hates leaks."

Barrack Obama: "I'm Really Good at Killing People"

Deadly strikes with the MQ-1 Predator drone and other unmanned aerial vehicles have grown considerably under the Obama Administration - and the President has defended the use of the tactic

The Obama administration also disputes drone casualty figures - though it has not released any numbers of its own to counter the independent studies.

Obama has defended his use of drones as being necessary for stopping terrorists in remote places before they can attack civilians.

"Let us remember that the terrorists we are after target civilians, and the death toll from their acts of terrorism against Muslims dwarfs any estimate of civilian casualties from drone strikes," he said in a speech at the National Defense University in May.

In October 2009, the Norwegian Nobel Committee - appointed by the Norwegian Parliament - gave Obama the Peace Prize for his "extraordinary efforts"to strengthen democracy, specifically citing his goals of nuclear disarmament.