Presidential candidate Bernie SandersBernard (Bernie) SandersOvernight Defense: Senate passes 0B defense bill | 3,000 US troops heading to Afghanistan | Two more Navy officials fired over ship collisions Senate passes 0B defense bill Dems fear lasting damage from Clinton-Sanders fight MORE repeated Sunday that Bill ClintonBill ClintonGOP rep: North Korea wants Iran-type nuclear deal Lawmakers, pick up the ball on health care and reform Medicaid The art of the small deal MORE’s past marital infidelities are “deplorable” but indicated he isn’t interested in talking about them.

“That question annoys me,” Sanders said at the Democratic debate in South Carolina when asked whether he regretted calling the former president's actions “totally disgraceful and unacceptable.”

“I cannot walk down the street — Secretary Clinton knows this — without being told how much I have to attack Secretary Clinton,” Sanders said of his rival for the party's nomination, former Secretary of State Hillary ClintonHillary Diane Rodham ClintonBiden slams Trump over golf gif hitting Clinton Overnight Cybersecurity: Equifax hit by earlier hack | What to know about Kaspersky controversy | Officials review EU-US privacy pact Overnight Tech: Equifax hit by earlier undisclosed hack | Facebook takes heat over Russian ads | Alt-right Twitter rival may lose domain MORE.

After Sanders made the comment, Clinton adviser John Podesta attacked him. The senator on Sunday insisted he would not engage in negative campaigning against Hillary Clinton.

“I have avoided doing that, trying to run an issue-oriented campaign,” he said to huge applause from the audience. 

Asked by NBC reporter Andrea Mitchell why he answered the question, Sanders said: “I was asked a question. Then if I don't answer, then it's another front-page story.

“Yes, his behavior was deplorable,” Sanders continued. “But I'm going to debate Secretary Clinton and Gov. [Martin] O'Malley on the issues facing the American people” and not on Bill Clinton's personal life.

Republican front-runner Donald Trump has repeatedly used the former president's sex scandals as lines of attack, calling him “one of the great woman abusers of all time.”

The real estate mogul has defended his remarks, saying Bill Clinton is fair game after Hillary Clinton accused Trump of having a “penchant for sexism.”