MISHAWAKA, Ind. — A political tempest over Barack Obama's comments about bitter voters in small towns has given rival Hillary Rodham Clinton a new opening to court working-class Democrats 10 days before Pennsylvanians hold a primary that she must win to keep her presidential campaign alive.

Obama tried to quell the furor yesterday, explaining his remarks while also conceding he had chosen his words poorly.

"If I worded things in a way that made people offended, I deeply regret that," Obama said in an interview with the Winston-Salem (N.C.) Journal.

But the Clinton campaign fueled the controversy in every place and every way it could, hoping charges that Obama is elitist and arrogant will resonate with the swing voters the candidates are vying for not only in Pennsylvania, but in upcoming primaries in Indiana and North Carolina as well.

Political insiders differed on whether Obama's comments, which came to light Friday, would become a full-blown political disaster that could prompt party leaders to try to steer the nomination to Clinton even though Obama has more pledged delegates. Clinton supporters were eagerly hoping so.

They handed out "I'm not bitter" stickers in North Carolina, and held a conference call of Pennsylvania mayors to denounce the Illinois senator. In Indiana, Clinton did the work herself, telling plant workers in Indianapolis that Obama's comments were "elitist and out of touch."

At issue are comments he made privately at a fundraiser in San Francisco last Sunday. He was trying to explain his troubles winning over some working-class 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."

The comments, posted Friday on The Huffington Post Web site, set off a blast of criticism from Clinton, Republican nominee-in-waiting John McCain and other GOP officials, and drew attention to a potential Obama weakness — the image some have that the Harvard-trained lawyer is arrogant and aloof.

His campaign scrambled to defuse possible damage.

There has been a small "political flare-up because I said something that everybody knows is true, which is that there are a whole bunch of folks in small towns in Pennsylvania, in towns right here in Indiana, in my hometown in Illinois, who are bitter," Obama said yesterday morning at a town hall-style meeting at Ball State University in Muncie, Ind.

"They are angry. They feel like they have been left behind. They feel like nobody is paying attention to what they're going through.

"So I said, well, you know, when you're bitter you turn to what you can count on. So people, they vote about guns, or they take comfort from their faith and their family and their community. And they get mad about illegal immigrants who are coming over to this country."

After acknowledging his previous remarks in California could have been better phrased, he added:

"The truth is that these traditions that are passed on from generation to generation, those are important. That's what sustains us. But what is absolutely true is that people don't feel like they are being listened to."

Clinton attacked Obama's remarks much more harshly yesterday than she had the night before, calling them "demeaning."

"People don't need a president who looks down on them," she said. "They need a president who stands up for them."