'He is a loser’: Biden lets rip on Donald Trump in South Carolina church speech

President Joe Biden seemed to rebuke Republican presidential candidate Nikki Haley on Monday after she failed to cite slavery as the cause of the U.S. Civil War. He also slammed Donald Trump's claim that the 2020 presidential election was rigged.

While speaking at Mother Emanuel AME Church in Charleston, South Carolina, Biden addressed Haley's remarks without saying her name.

"So they say they embraced what's known as the lost cause, a self-serving lie that the Civil War is not about slavery, but about states' rights," he said. "They've called that the noble cause. That was a lie, a lie that had not just a lie, but had terrible consequences. It brought on Jim Crow."

"So let me be clear, for those who don't seem to know, slavery was the cause of the Civil War," he added. "There was no negotiation about that."

The remarks came after Haley was asked what caused the Civil War at a town hall event in New Hampshire.

ALSO READ: Run on broken Senate record? Nope. One embattled Dem senator explains his all-in strategy.

"I think the cause of the Civil War was basically how government was going to run — the freedoms and what people could and couldn't do," she replied, adding, "We need to have capitalism. We need to have economic freedom. We need to make sure that we do all things so that individuals have the liberties so that they can have freedom of speech, freedom of religion, freedom to do or be anything they want to be without government getting in the way."

The GOP candidate later clarified her answer to include slavery.

On Monday, Biden also took a shot at former President Donald Trump's claim that the 2020 presidential election was rigged.

"Those pushing the big lie have a conspiracy theory among conspiracy theories that outweighs them all," Biden said. "Their whole theory has no facts, has no proof, has no evidence. That's why, time and again, they lost in every court of law that challenged the results. Sixty losses in courts of America."

"In America, we all count," he added. "In America, we witness to serve all those who, in fact, participate. And losers are taught to concede when they lose. He's a loser."

In 2015, a white supremacist shot and murdered nine people at Mother Emanuel AME Church.

Watch video clips from Biden's speech below.