Joe Biden and Sen. Bernie Sanders clashed at Sunday night's Democratic primary debate as they reignited a fight over the former vice president's record on Social Security.

The two remaining major candidates in the nomination race faced off for four straight minutes over whether Biden – as a senator from Delaware a quarter-century ago – had called for cuts to Social Security as well as Medicare and veterans programs.

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The latest clash kicked off as Biden charged “my lord Bernie, you’re running negative ads saying I’m opposed to Social Security that Politifact says is a flat lie and that the Washington Post says is a flat lie.”

The TV commercial in question includes an audio clip from decades ago of then-Sen. Biden saying “when I argued that we should freeze federal spending, I meant Social Security as well. I mean Medicare and Medicaid. I meant veterans' benefits. I meant every single solitary thing in the government.”

Politifact and the Washington Post both rated the claims “misleading,” as Biden has held various positions but eventually backed increases.

The populist senator from Vermont who’s making his second straight White House run fired back.

“Let me ask you a question Joe. You’re right here with me. Have you been on floor of the Senate – you were in the Senate for a few years – time and time again talking about the necessity to with pride about cutting Social Security, cutting Medicare, cutting Veterans programs?” Sanders asked.

“No,” Biden quickly answered.

“You never said that,” Sanders responded.

“No,” Biden shot back.

“Alright. America, go to the website right now. Go to the YouTube right now,” Sanders urged.

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Sanders then asked Biden “you were not a fan of the balanced budget amendment which called for cuts to Social Security? Come on Joe. You were. You’re an honest guy. Why don’t you just tell them the truth here. We all make mistakes.”

Biden responded, “I am telling the truth.”

Sanders repeated his question, saying “Joe, let me repeat it again. I want you to just be straight with the American people. I am saying that you have been on the floor of the U.S. Senate time and time again talking about the need to cut Social Security, Medicare, veterans program. Is that true or not true?”

“No. That’s not true,” Biden fired back.

“That is not true?” Sanders asked?

Biden then said “what is true is in terms of the negotiations that were taking place in how to deal with the deficit, everything was on the table. I did not support any of those cuts in Social Security or veterans affairs.”

“Whoa, whoa, whoa. Everything was on the table,” Sanders interrupted. “Alright. You’re right. And you just said it. Including in your judgment cuts to Social Security and veterans.”

Biden shot back that “in order to get the kinds of changes we need on other things. But we did not cut it.”

“I know. Because people like me help stop that,” Sanders touted.

And he claimed that “Joe. You just contradicted yourself.”

Immediately after the debate stage clash, the Sanders campaign tweeted out C-SPAN video of the Biden comments from 25 years ago.