(ABC News)

This morning on "This Week," New York Times columnist Paul Krugman called Rep. Paul Ryan's proposed budget plan a "fraud" as Romney campaign senior advisor Eric Fehrnstrom confirmed his candidate's support for the plan that would trim trillions in federal spending over the next decade.

"The Ryan plan - and I guess this is what counts as a personal attack - but it isn't.  It's not an attack on the person; it's an attack on the plan.  The plan's a fraud," said Krugman. "And so to say that - just tell the truth that there is really no plan there, neither from Ryan, nor from Governor Romney, is just the truth.  That's not - if that's - if that's being harsh and partisan, gosh, then I guess the truth is anti-bipartisanship. "

Krugman, who has been critical of the Ryan, R-Wis., plan in the past, was responding to the Fehrnstrom, who confirmed Romney's support for the plan after ABC News' George Will asked Fehrnstrom to clarify his candidate's stance on the Ryan proposal.

"He's for the Ryan plan.  He believes it goes in the right direction.  The governor has also put forward a plan to reduce spending by $500 billion by the year 2016," said Fehrnstrom. "In fact, he's put details on the table about how exactly he would achieve that.  So to say he doesn't have a plan to - a plan to restrain government spending is just untrue."

Krugman defended the president's budget plan when asked by Fehrnstrom if he preferred it over the Ryan plan.

"I mean, the president - at least it's - you know, I don't approve of everything, but there are no gigantic mystery numbers in his stuff.  We do know what he's talking about.  His numbers are - you know, all economic forecasts are wrong, but his are not - are not insane.  These are - these are just imaginary," he said.