Democrats and Republicans have yet to choose their official candidates for next year's presidential election, but that has not stopped front-runners Hillary Clinton and Donald Trump from attacking each other.
Monday began with Trump calling Clinton a liar and demanding she apologize for her claim during Saturday's Democratic debate that Islamic State militants are using videos of his comments as a recruiting tool. Her campaign later said they were not aware of a specific video, but that Trump's comments about Muslims are helping jihadists.
A Clinton spokesman, speaking to CNN, put the response to Trump simply: "Hell no."
"Hillary Clinton will not be apologizing to Donald Trump for correctly pointing out how his hateful rhetoric only helps ISIS recruit more terrorists," spokesman Brian Fallon said, using an acronym for the militant group.
The former Secretary of State brought a moment of comic relief during Saturday's debate when after a commercial break she strode back to her podium late, the result of what her campaign said was a long walk to the women's restroom at the site.
Trump brought that up at an event Monday night among several personal attacks as he spoke to his supporters.
"I know where she went. It's disgusting. I don't want to talk about it," he said.
The billionaire also cited the 2008 election when President Barack Obama defeated Clinton for the Democratic Party nomination. Trump, who has been criticized for his comments about women, used a vulgar term involving male anatomy to describe Clinton's loss in a race she was favored to win.
The parties begin the official selection process with the Iowa caucuses February 1, and will crown their nominees next July.
Both Trump and Clinton lead their races by wide margins, but an average of the latest national polls shows Clinton beating Trump in a hypothetical race by six points.