PITTSBURGH, Pennsylvania (CNN) - On Monday, with the Pennsylvania primary just days away, Hillary Clinton continued to hammer Barack Obama over his comments that small town Americans "cling to guns or religion" because they are "bitter."
But the audience at a forum put on by the Alliance for American Manufacturing didn't appreciate her line of attack.
"I understand my opponent came this morning and spent a lot of his time attacking me," she said at the beginning of her remarks here.
Many in the crowd responded with audible groans, and a few shouted, "No!"
Obama spoke to the same forum earlier in the morning and ribbed Clinton for doing a shot of whiskey in front of TV cameras on Saturday in Indiana.
Clinton continued, "I know that many of you, like me, were disappointed by the recent remarks he made."
This time, a louder, sustained chorus of "No!" emanated from the audience. Clinton soldiered on.
"I am well aware that at a fundraiser in San Francisco he said some things that many people in Pennsylvania and beyond Pennsylvania have found offensive," she said.
This time, a smaller smattering of jeers.
It was only when Clinton concluded her opening remarks by attacking President Bush that she received a warm round of applause.
The Clinton campaign later said the disgruntled reaction to her remarks came from Obama supporters in attendance.
Several audience members told CNN after the speech they came to the forum to hear each candidate talk about trade issues, and were not interested in the political back-and-forth of the Democratic primary race.
When Clinton focused on policy and expounded on enforcing trade agreements, creating new jobs and standing up to China, she received some hearty ovations.
But despite Pittsburgh's working class reputation, it was at times a tough crowd for the New York senator.
As the question and answer session began, one man asked Clinton for assurances that American workers would not be "tricked" like they had been when her husband signed NAFTA in 1993.
A press release distributed to reporters by the Alliance for American Manufacturing calculated that Pennsylvania lost 44,173 jobs due to NAFTA between 1993 and 2004.
Clinton, who spent much of her speech attacking America's trade imbalance with China, responded by drawing a line in the sand between her policy positions and her husband's trade record.
"As smart as my husband is, he does make mistakes," Clinton quipped.