President Barack Obama has revealed that Secret Service has rejected his request to convert his presidential limousine into a hybrid vehicle due to security reasons.

"I asked can we make these cars hybrids Secret Service said no. Now, the reason is not because Secret Service are bad guys. It's because the cars that I'm in are like tanks," ABC News quoted Obama, as saying at a town hall in Charlotte, North Carolina yesterday.

Obama clarified that since his limo - nicknamed "the beast" - is reinforced for security reasons, and weighs over two times the normal weight of cars, "they just couldn't get the performance in terms of acceleration using a hybrid engine.”