Mitt Romney is a bullshitter: Barack Obama

While presidential battles are never fought with sweet talk, US President Barack Obama took his opponent bashing to a new level when he termed his Republican challenger Mitt Romney a "bullshitter".

The remarks that came in an interview to Rolling Stone magazine were essentially a light hearted aside, but led to many a raised eyebrow.

Obama has repeatedly called Romney untrustworthy for his changing positions on major issues and even coined a whole new term for his condition -- Romnesia.

This time, however, the President took it a notch higher when responding to a suggestion on his popularity in kids, he said the young ones could see who was a 'bullshitter'.

"You know, kids have good instincts," Obama offered.

"They look at the other guy and say, 'Well, that's a bullshitter, I can tell," the US President said.

Obama said this when the editor interviewing the President told him that his six-year-old had asked him to convey to Obama that 'You can do it'.

"That's the only advice I need," he said.

"I do very well, by the way, in that demographic. Ages six to 12? I'm a killer," he joked.

Obama also said that by the next Halloween he hopes Romney will be an ex-presidential candidate.

 The Obama Campaign later asked journalists not to get "distracted by the word".

"The president is someone who says what he means and does what he says," spokesman Dan Pfeiffer tried to clarify.

During the interview, Obama also spoke about his "terrific relationship" with former president Bill Clinton, who he said was regularly giving him good advice.

"Not only is he a great politician, but he's also somebody who has a lot of credibility with the public when it comes to how the economy works. Because the last time we had healthy, broad-based growth was when he was president, and people remember that. So he can say things that people immediately grab on to.

"And one of the things he said during the convention that I thought was very helpful was to put this whole economic crisis in context," Obama said.

He said that unlike Franklin D Roosevelt who came into office when the economy had already bottomed out, he himself assumed office when things were "sliding".

"Because of the actions we took, we averted a Great Depression -- but in the process, we also muddied up the political narrative, because it allowed somebody like Romney to somehow blame my policies for the mess that the previous administration created.

"Bill Clinton can point that out in ways that are really helpful and really powerful," Obama said.