HAMPTON, N.H. — Former Vice President Joe Biden offered a puzzling response to a voter who asked how he can be expected to win a national election after placing fourth in Iowa.

At a campaign event in New Hampshire, the woman warned Biden that she was about to ask a potentially mean question before saying, "How do you explain the performance in Iowa, and why should voters believe that you can win the national election?"

Biden said the question was legitimate but then asked whether she had "ever been to a caucus" before.

She signaled that she had, to which Biden said: "No, you haven't. You're a lying dog-faced pony soldier." The audience laughed in response.

The comment is a reference to a line Biden has used before, one he has claimed is from a John Wayne movie. As he finished answering the woman's question, Biden said it was "not a mean question" but "an honest question."

It's unclear what movie Biden was referring to. The woman told The Washington Post that she was surprised by his reaction.

"I'm not one to just push on wounds. I'm not trying to humiliate anyone,” she said.

Scrutiny of Biden's campaign has intensified in recent days following his underwhelming performance in Iowa.

New Hampshire polling has virtually flipped in the days after the Iowa vote. About three weeks ago, Biden held a 10-point edge on Pete Buttigieg, the former mayor of South Bend, Indiana, in the Granite State; he now trails Buttigieg by about 10 points. The polls show Sen. Bernie Sanders, I-Vt., in the top spot, according to the RealClearPolitics average of several surveys.

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Buttigieg holds a 10-point lead on Biden in a CNN/University of New Hampshire poll released this weekend. And he holds an 8-point lead over Biden in an NBC News/Marist poll released Friday.

The exchange brought back memories of an exchange Biden had with a voter in December, when he called an Iowa voter a "damn liar" and challenged him to a push-up contest after the man questioned his age and dealings with Ukraine.