Republican vice presidential candidate Paul Ryan appears at the AARP convention on Sept. 21. (Bill Haber/AP)

— 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 from Woodbridge, accused the other side of advancing ideas that would undermine and destroy the popular health-care program for the elderly 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.”

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 that is the president’s signature legislative and policy achievement. 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 took the stage and addressed the audience of several thousand people less than an hour later, he returned fire: “You know President Obama’s slogan, right?” he asked the audience. “ ‘Forward’ — forward into a future where seniors are denied the care they earned because a bureaucrat decided it wasn’t worth the money.”

As he did at a Florida retirement community event last month, Ryan attacked Obama’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 that he would repeal Obama’s health-care law. Several attendees yelled out “Liar!” and “No vouchers!” during his speech. At one point, when Ryan told the crowd that “all that we need now is leaders who have the political will to save and strengthen Social Security,” one man quipped: “Got one!”

Asked later what he thought of the audience reaction at the AARP event, Ryan chalked it up to the fact that “entitlement reform has unfortunately been made very partisan, by partisans.”

“Unfortunately, it’s what we’ve come to expect because the politics of reforming entitlements has become very bitter,” he said in a brief exchange with reporters during a stop at a fruit stand in Bartow, Fla.

The dueling speeches came as Romney sought to put a difficult campaign week behind him. Additionally, Ann Romney’s plane made an emergency landing in Colorado early Friday evening. Aides said that the plane, which was en route from Omaha to Los Angeles, filled with smoke and that no one was injured.

With multiple swing-state polls showing the GOP ticket losing ground to Obama, a key to victory in several of those battleground states will be seniors, among whom Medicare reform is a top election-year issue.

A Washington Post-Kaiser Family Foundation poll last month showed that 58 percent of all adults support allowing Medicare to continue as it is today, while 36 percent support a plan that would make the changes that Ryan has advocated.

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

Speaking to a crowd of 12,000 in Woodbridge, 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’s “60 Minutes” set to air Sunday, Romney pushed back against the suggestion that his slip in the polls as well as a video released this week of his remarks at a private fundraiser should be cause for concern among Republicans.

“Well, it doesn’t need a turnaround,” Romney said of his campaign. “We’ve got a campaign which is tied with an incumbent president to the United States.”

Nakamura reported from Washington.Amy Gardner in Woodbridge and Nia-Malika Henderson in Las Vegas contributed to this report.