EXETER, N.H. — Senator Bernie Sanders had just finished addressing supporters here Saturday afternoon, reprising his stump speech standards about raising the minimum wage, addressing climate change and implementing universal health care when a voter raised her hand to ask about a topic he didn’t mention but which had increasingly loomed over the race.

How do Democratic presidential candidates, the voter asked without directly mentioning Mr. Sanders’s clash with Senator Elizabeth Warren, avoid infighting?

Mr. Sanders, of Vermont, briefly criticized the news media — which he said “often wants and exaggerates conflict” — before noting he had not targeted any of his rivals in his remarks.

“The best thing for all the Democratic candidates,” he said, was to “focus on issues of the working families of America.”

Yet after Mr. Sanders and Ms. Warren, of Massachusetts, angrily accused one another of lying about whether he had told her a woman could not defeat President Trump, and with just over two weeks until the Feb. 3 Iowa caucuses, supporters of the two progressives and erstwhile political allies remained upset.

“I was really disappointed,” said Jayne Cousins, an ardent Sanders supporter who attended his rally here. She predicted Ms. Warren’s claim, which Mr. Sanders denies, would adversely impact Ms. Warren because, she said, it was so implausible.

But when Ms. Warren returned to Iowa for the first time since her confrontation with Mr. Sanders on the debate stage in Des Moines, it was not difficult to find voters who said the opposite: that Mr. Sanders would pay a price for what they saw as his insensitivity on one of the most fraught issues in the primary.

“I have a lot of friends who said they won’t vote for him,” because of the incident, said David Jansen, who attended Ms. Warren’s town-hall-style meeting in Newton, Iowa, on Friday.

The tensions between the two candidates began a week ago, after a report that Mr. Sanders’s campaign had told its field organizers to characterize Ms. Warren’s base as affluent and elite, which caused the Massachusetts senator to say she was “disappointed” in Mr. Sanders.