NEW ORLEANS - GOP vice-presidential nominee Paul Ryan's plan to overhaul Medicare returned to the political spotlight Friday as both presidential campaigns jabbed each other during a summit of the AARP, the country's top advocacy group for seniors.

Both Ryan, who addressed the group in person, and President Obama, who spoke ahead of Ryan via a video feed, accused the other side of advancing ideas that would undermine and destroy the popular health care program for seniors and the disabled.

"I don't consider this approach bold or particularly courageous," Obama said of Ryan's Medicare overhaul proposal "I just think it's a bad idea. No American should spend their golden years at the mercy of insurance companies."

Allegations 'simply not true'

Obama defended himself against the allegation that his administration "somehow took $716 billion and robbed it from Medicare beneficiaries" as part of the 2010 health care law, which closed a gap in coverage for seniors' prescription drugs. Ryan and GOP presidential nominee Mitt Romney regularly argue that the Obama law would harm the program by removing that money.

It is "simply not true," Obama said.

When Ryan addressed the audience of several thousand people less than an hour later, he returned the fire: "You know President Obama's slogan, right?" Ryan said. "'Forward' -- forward into a future where seniors are denied the care they earned because a bureaucrat decided it wasn't worth the money."

Ryan attacked the president's plan in great detail, and pitched his plan in personal terms with fewer specifics, noting that his 78-year-old mother was in attendance at the event.

Many in the audience booed Ryan, particularly when he vowed to repeal the health care law. Several yelled "Liar!" and "No vouchers!" At one point, when Ryan said that "all that we need now is leaders who have the political will to save and strengthen Social Security," one man quipped: "Got one!"

The dueling speeches came as Romney seeks to put a difficult week behind him and with multiple swing state polls showing the GOP ticket losing ground to Obama. Central to victory in several of those states will be seniors, among whom Medicare reform is a top election-year issue.

Romney touts housing policy

While the White House hopefuls at the AARP summit focused on Medicare reform, elsewhere on the trail the candidates focused on the other issues that have animated the campaign as of late.

Speaking to a crowd of 12,000 in Woodbridge, Va., Obama mocked Romney for pledging at a rally on Thursday to change Washington "from the inside." "What kind of inside job is he talking about? Is it the job of rubber-stamping the top-down, you're-on-your-own agenda of this Republican Congress?" Obama asked.

At his rally in Las Vegas, Romney touted his campaign's newly-released housing policy white paper, which calls for reforming Fannie Mae and Freddie Mac and selling the estimated 200,000 vacant foreclosed homes currently owned by the federal government.

And in an interview for CBS' "60 Minutes" set to air Sunday, Romney pushed back against the suggestion that his slip in the polls as well as video of his remarks that his job as a candidate is not to worry about the 47 percent of Americans whom he said pay no taxes and see themselves as victims should be cause for concern. "Well, it doesn't need a turnaround," he said of his campaign.