STEELTON (AP) _ Accused of being elitist, a defiant Sen. Barack Obama lashed out at rival Sen. Hillary Rodham Clinton, saying "Shame on her" and mocking her vocal support for gun rights as their political tempest threatened to consume the Democratic presidential race.

It was a startling twist Sunday to the three-day controversy that erupted after the publication of comments the Illinois senator made at a San Francisco fundraiser a week earlier. At that event, Obama said some working-class voters are bitter over their economic circumstances and "cling to guns and religion" as a result.

Campaigning Sunday in Pennsylvania, Clinton derided the comments as "elitist and divisive" and suggested they could doom Democrats' chances for recapturing the White House in November if Obama were the nominee.

At a union hall outside Harrisburg, Obama said he'd expected blowback from GOP nominee-in-waiting John McCain but said he'd been "a little disappointed" to be criticized by Clinton.

Laughing, the Illinois senator noted Clinton seemed much more interested in guns since he made his comments than she had been in the past. On Saturday, the former first lady reminisced about learning to shoot on summer vacations in Scranton, where her father grew up.

"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 said.

Clinton has told campaign audiences that she supports the rights of hunters. She's also said she once shot a duck in Arkansas, where she served as first lady.

Clinton, who is trailing Obama in the popular vote and pledged delegates, has pounded Obama since audio from his San Francisco appearance was posted on The Huffington Post Web site. She hoped the comments might give her a new opening to court working-class Democrats less than 10 days before the Pennsylvania primary on April 22, which she needs win to keep her campaign going.

At the San Francisco fundraiser, Obama tried to explain his troubles in winning over some blue-collar voters, saying they have become frustrated with economic conditions: "It's not surprising, then, they get bitter, they cling to guns or religion or antipathy to people who aren't like them or anti-immigrant sentiment or anti-trade sentiment as a way to explain their frustrations."

In Scranton on Sunday, Clinton said Obama's words would probably alienate voters in Pennsylvania and other states holding primaries in the coming weeks. Indiana and North Carolina vote on May 6.

"How does he see people here in this neighborhood, throughout Pennsylvania, Indiana, North Carolina, other places in our country?" she asked during an informal news conference. "I think that's what people are looking for, some explanation, and he has simply not provided one."

Fighting back, Obama said Clinton's history proved she was not as sensitive to the concerns of blue-collar voters as she claimed. He noted that Clinton accepted campaign contributions from political action committees and drug and insurance industry lobbyists, which he does not.

"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, which is widely unpopular among blue-collar voters.

Obama's comments came up later Sunday in a forum on faith and values at Pennsylvania's Messiah College.

"What I was saying is that when economic hardship hits in these communities, what people have is they've got family, they've got their faith, they've got the traditions that have been passed onto them from generation to generation," Obama said at the forum, which was televised on CNN. "Those aren't bad things. That's what they have left."

Obama planned to address the issue of which candidate was most in touch with working voters in a speech before the annual meeting of The Associated Press in Washington on Monday.

Clinton stuck with her criticism of Obama at the Sunday night forum but said she didn't believe his words implied he lacked religious faith.

"Someone goes to a closed-door fundraiser in San Francisco and makes comments that do seem elitist, out of touch and, frankly, patronizing," she said. "That has nothing to do with him being a good man or a man of faith."