Republican vice-presidential candidate Sarah Palin defended her claim that Democrat Barack Obama "pals around with terrorists," saying his association with a Vietnam-era radical is an issue that is "fair to talk about."

The Associated Press reports that Obama has denounced the radical views and actions of Bill Ayers, a founder of the 1960s violent Weather Underground group. On Sunday, the presidential hopeful tossed aside the criticism from the McCain-Palin campaign as "smears" meant to distract voters from real problems.

Palin lobbed the verbal attack several times over the weekend.

"The comments are about an association that has been known but hasn’t been talked about," Palin said. "I think it’s fair to talk about where Barack Obama kicked off his political career, in the guy’s living room."

Later, at an Omaha rally in which Palin helped raise $2.5 million for the campaign, the Alaska governor claimed one of Obama’s advisers had described Obama and Ayers as "friendly."

Obama and Ayers both have volunteered for the same Chicago charity and live near each other in Chicago. Ayers held an Obama event at his home when the candidate first ran for office in the mid-1990s.

During a North Carolina rally, Obama described the criticism as "Swiftboat-style attacks" on him.

In an interview with Weekly Standard editor and New York Times columnist Bill Kristol, Palin also said the media should not have let go Obama’s association with his former firebrand pastor, Rev. Jeremiah Wright.

"I don’t know why that association isn’t discussed more, because those were appalling things that that pastor had said about our great country, and to have sat in the pews for 20 years and listened to that — with, I don’t know, a sense of condoning it, I guess, because he didn’t get up and leave — to me, that does say something about character," Palin told Kristol in a phone interview. "But, you know, I guess that would be a John McCain call on whether he wants to bring that up.”