Joe Biden came under fire Tuesday from 2020 rival Tom Steyer after a video surfaced of him telling a man in Iowa to “go vote for someone else” when the man challenged him on his energy policies in the Hawkeye State.

The man, identified as Ed Fallon, took the opportunity during Biden's appearance at a campaign event to grill him on energy policies.

"I'm going to support you if you win the nomination because we've got to get rid of Trump. What are we going to do about climate change?" asked Fallon, a former state legislator. “Now you say you’re against pipelines but then you want to replace these gas lines... We have got to stop building and replacing pipelines."

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“No no no... go vote for someone else,” Biden said while patting him on the chest. "You’re not going to vote for me in the primary.”

“I’m going to vote for you in the general if you treat me right,” Fallon said.

“Look, you’re asking for a picture of me, coming up and telling me you don’t support me,” Biden said, to which Fallon disagreed, saying he’d back him in the general.

“I’m looking for a primary, caucus [vote],” Biden told Fallon, who said he's supporting Steyer in the caucuses next week. Fallon then asked for a picture, to which Biden said no.

The exchange went viral online after video from journalist Zaid Jilani surfaced, and it soon brought criticism from Steyer, who said it was “no way to treat an Iowan.”

“He said he'd vote for the Dem in the general [because] he knows how important it is to beat Trump,” Steyer tweeted Tuesday. We need immediate action on climate. If you don't agree, happy to talk @ debate.”

“But don't take it out on voters we need to win in [November],” he added.

Fallon, meanwhile, took to his website, BoldIowa.com, to give his account of the interaction, where he accused Biden of not even attempting to address his concern.

“What was even more shocking was how Biden pushed and poked me, and then took hold of my jacket with both hands as he lectured me,” he wrote.

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“I’ve said this before, and I’ll say it one more time: Joe Biden is the Democratic candidate LEAST likely to beat Donald Trump,” Fallon wrote. “His demeanor on the stump will inevitably come back to bite him, perhaps repeatedly."

The Biden campaign did not immediately respond to Fox News' request for comment.