The Associated Press

Some admittedly poorly chosen words by U.S. Sen. Barack Obama, D-Ill., opened the door for U.S. Sen Hillary Clinton to call his remarks elitist and question Obama's connection with everyday people.

At issue are comments he made April 6 at a private fundraiser in San Francisco. 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."

Clinton's campaign leapt.

In Valparaiso and Indianapolis, Clinton, D-N.Y., called Obama's remarks "elitist and out of touch." In North Carolina, Clinton supporters distributed "I'm not bitter" bumper stickers. In Pennsylvania, Clinton's camp held a conference call of state mayors to denounce Obama.

McCain's campaign piled on, releasing a statement that accused Obama of elitism.

Obama on Saturday tried to explain his remarks and conceded 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.

Obama said he meant to express that many voters feel abandoned and unheard.

It remains to be seen whether the remarks might affect the convention, where the race might be decided. Neither candidate is thought to have enough for nomination without help from unpledged party officials known as superdelegates.