STEELTON, Pa. -- Barack Obama lashed out Sunday at Democratic rival Hillary Clinton, mocking her sudden vocal support for gun rights, and saying he better understands the concerns of working class people.

The Illinois senator has spent three days on the defensive after comments he made at a San Francisco fundraiser suggesting working class people are bitter about their economic circumstances and "cling to guns and religion" as a result. Clinton has pounded him for the remarks, calling him "elitist and divisive."

"Now I am the first to admit that some of the words I chose I chose badly, because as my wife reminds me, I’m not perfect. She reminds me of this frequently, and events often remind me as well," Obama said, reiterating his regret for his choice of words.

"So I’m not a perfect man and the words I chose, I chose badly. They were subject to misinterpretation, they were subject to be twisted, and I regret that. I regret that deeply. But. But. But. When people suggest that somehow I was demeaning religion. When I know that I’m a man of deep faith, somebody who in my own life has held on to faith, held onto my confidence in God during times of trial and tribulation, then it sounds like there’s some politics being played.

"When people suggest I was somehow being elitist and demeaning hunters when I have repeatedly talked about the tradition that people pass on from generation to generation, hunters and sportsmen, and how I have consistently spoken about my respect for the Second Amendment. When people try to suggest that I was demeaning those traditions, then it sounds like there’s some politics being played. And what really burns me up is when people suggest that me saying that folks are mad, they are angry, they are bitter after 25, 30 years of seeing jobs shipped out, pensions not fulfilled, health care lost. The notion that people are surprised, and are suggesting that I’m out of touch because I spoke honestly about people’s frustrations, that tells me there’s some politics going on," he said.

He then turned the tables on Clinton -- noting that she accepted campaign contributions from drug and insurance company lobbyists and mocking, among other things, her sudden fealty to the rights of gun owners.

"She is running around talking about how this is an insult to sportsmen, how she values the Second Amendment. She's talking like she's Annie Oakley," Obama told an audience at a union hall here, invoking the famed female sharpshooter immortalized in the musical "Annie Get Your Gun."

Obama continued, saying "Hillary Clinton is out there like she's on the duck blind every Sunday. She's packing a six-shooter. Come on, she knows better. That's some politics being played by Hillary Clinton. ... She knows better. Shame on her. Shame on her."

Obama said the former first lady's history in the White House and Senate proved she was not as sensitive to the concerns of working class voters in Pennsylvania and elsewhere as she tried to suggest. Pennsylvania's primary is April 22.

"I just have to remind people of the track record," Obama said. "This is the same person who took money from financial folks on Wall Street and then voted for bankruptcy bill that makes it harder for folks right here in Pennsylvania to get a fair shake. Who do you think is out of touch?

"This is the same person who spent a decade with her husband campaigning for NAFTA, and now goes around saying she's opposed to NAFTA," Obama said, referring to the North American Free Trade Agreement that is widely unpopular in blue collar communities.

Obama also pledged that he will be a different kind of politician.

"Every four years, we get politicians coming before you and they say the same things. They say that they’re gonna fight for you. They say they’re gonna bring all the jobs back. They say they’re gonna get health care done. They say they’re gonna make sure our trade deals are fair. You guys have been hearing that. You’ve been hearing it forever. And things haven’t changed. And of course you’re frustrated about that. Of course you’re angry about that. Of course you’re bitter about that. But here’s the good news: the good news is, that when we started this campaign we said we were gonna do something different," he said.

The Clinton campaign issued a quick retort to Obama's comments.

"For months, Barack Obama and his campaign have relentlessly attacked Hillary Clinton's character and integrity by using Republican talking points from the 1990s," said spokesman Phil Singer. "The shame is his. Senator Clinton does know better -- she knows better than to condescend and talk down to voters like Senator Obama did."

In an interview on CNN on Sunday evening, Clinton said that Obama's comments raise a legitimate political issue.

“Someone goes to a closed-door fundraiser in San Francisco and makes comments that do seem elitist, out of touch and frankly patronizing. That has nothing to do with him being a good man or a man of faith. We had two very good men and men of faith run for president in 2000 and 2004 but large segments of the electorate concluded that they did not really understand or relate to or frankly respect their ways of life. And I think that is an issue for voters as I've heard today from people I visited in Scranton and elsewhere."

FOX News' Aaron Bruns and The Associated Press contributed to this report