Elizabeth Warren has accused fellow Democrat Bernie Sanders of calling her a liar on national television, moments after the Democratic debate ended on Tuesday (local time).
Warren is seen walking over and refusing to shake Sanders' outstretched hand before the pair engage in a heated exchange.
The video of the senators' exchange aired live with no audio, so all audience members and viewers at home saw was the pair in a fiery discussion, before Sanders threw his hands in the air and walked away.
Debate broadcaster CNN later released the video with audio included.
"I think you called me a liar on national TV," Warren said. She repeats herself after Sanders responds with "what?".
"Let's not do it right now. You want to have that discussion, we'll have that discussion," Sanders said.
"Anytime," Warren responded.
"You called me a liar, you told me- alright let's not do it now," Sanders said.
After their exchange, Democratic candidate Tom Steyer, who was standing behind the senators during their dispute, said "I don't want to get in the middle. I just want to say hi Bernie".
Their end-of-debate conversation occurred before their lapel microphones were removed. CNN said they did an inventory of the audio equipment used during the debate and found backup recordings from the microphones Warren and Sanders were wearing.
CNN then synchronised the audio recordings with the debate footage.
Warren and Sanders sparred during the debate over whether Sanders told her in a private meeting that a woman couldn't win the White House in 2020.
Sanders denied making the 2018 comment, saying during the debate it's "incomprehensible" that he would think a woman couldn't be president.
"Go to YouTube today. They have some video of me 30 years ago talking about how a woman could become president of the United States," he said.
However, CNN reported that four sources confirmed to them that he had told Warren a woman couldn't win.