Susan Rice, who served as national security adviser during the Obama administration, referred to Sen. Lindsey Graham (R-S.C.) as a "piece of shit" during the taping of an episode of the "Pod Save the World" podcast this week.

She made the remark after Tommy Vietor, another former Obama adviser, first used the term to refer to Graham during a discussion about the 2012 Benghazi attack in Libya.

"You have to understand Benghazi to understand [President] Trump," said Ben Rhodes, a deputy national security adviser during the Obama administration who is a host of the podcast.

"Right, because Lindsey Graham isn't just a piece of shit now," Vietor said before Rice interrupted.

"He's been a piece of shit," she said. "He's a piece of shit."

Graham's office did not immediately respond to a request for comment.

Rice, a critic of Trump's withdrawal of troops from northern Syria, was sharply criticized by Trump last week on Twitter, where the president slammed her and the Obama administration's refusal to take military action against the Syrian government after it used chemical weapons in the Syrian civil war.

"Susan Rice, who was a disaster to President Obama as National Security Advisor, is now telling us her opinion on what to do in Syria. Remember RED LINE IN THE SAND? That was Obama. Millions killed! No thanks Susan, you were a disaster," Trump tweeted.

Rice later responded to the president on Twitter, writing: "Then why did you come up and hug me at 2015 WHCD when I'd never met you (which was totally gross) and whisper in my ear that I had been 'very unfairly treated' over Benghazi and 'was doing a great job for the country'?"