(Winslow Townson/AP Photo)

By ALEX MARINO, MATTHEW LAROTONDA and DEVIN DWYER

WINDHAM, N.H. - President Obama today ratcheted up attacks on Mitt Romney over his personal tax rate, accusing the presumptive GOP nominee of choosing a running mate whose budget plan would reduce his tax burden to less than 1 percent each year.

"His new running mate, Congressman [Paul] Ryan, put forward a plan that would let Governor Romney pay less than 1 percent in taxes each year," Obama said on the stump in Windham, N.H.

"Here's the kicker: he expects you to pick up the tab. Governor Romney's tax plan would actually raise taxes on middle-class families with children by an average of $2,000. Not to reduce the deficit, or grow jobs, or invest in education ­but to give another tax cut to people like him," Obama said.

The charge is based on an analysis by Roll Call earlier this month of Ryan's "Roadmap for America's Future" 2010 budget, which would eliminate taxes on capital gains, dividends and interest - the primary sources of Romney's income. A separate study by the nonpartisan Tax Policy Center, disputed by the Romney campaign, found the Republican's plan would raise rates on lower-income earners.

"Ask Governor Romney and his running mate when they're here in New Hampshire on Monday - they're going to be coming here on Monday - ask them if they think that's fair. Ask them how it'll grow the economy, or strengthen the middle-class. They have tried to sell us this trickle-down snake oil before. It didn't work then and it won't work now," he said.

The Romney-Ryan campaign says Obama distorts the facts with his charge. Romney has said he opposes eliminating the capital gains tax for upper-income earners; elimination of the capital gains tax was also not in Ryan's most recent budget proposal from 2012. (See an ABC fact-check of Obama's claims HERE.)

"Following news that 44 out of 50 states saw their unemployment rates rise, it is not surprising the President is launching yet another false attack," Romney campaign spokesman Ryan Williams said. "The fact is President Obama wants to raise taxes on private investment and job creators, which will lead to higher unemployment and fewer jobs. The Romney-Ryan Plan eliminates taxes for the middle class on interest, dividends and capital gains and implements pro-growth policies to deliver more jobs and more take-home pay for middle-class families."

The president also swiped at his rivals for their Medicare plan and pushed back against recent attacks that he has undermined the program.

"You think they'd avoid talking about Medicare, given the fact that both of them have proposed to voucherize the Medicare system," Obama said.

"That doesn't strengthen Medicare; that undoes the very guarantee of Medicare. That's the core of the plan reached by Congressman Ryan and endorsed by Governor Romney," the president said, echoing his remarks in Iowa earlier this week.

Meanwhile, Ryan was in Florida at the nation's largest retirement community, The Villages, to make the case before hundreds of seniors that Obama has already ended Medicare as it is known, cutting $700 billion in spending on the program to help pay for the Affordable Care Act. Ryan also accused Obama of not putting forward a plan to address the entitlement's long-term financial solvency.