A feud between Melania Trump and Hunter Biden escalated Thursday after Biden refused to apologize for linking the former First Lady to convicted sex trafficker Jeffrey Epstein. In a recent YouTube interview with Andrew Callaghan, Hunter Biden alleged Epstein introduced Melania to Donald Trump—an unverified claim that Melania’s attorney, Alejandro Brito, called “false” and “extremely salacious.”

Brito sent a legal letter demanding a retraction and apology, threatening a $1 billion defamation lawsuit for the alleged reputational harm. However, when invited back to Callaghan’s show, Biden responded defiantly: “F— that, that’s not going to happen.” He cited Michael Wolff’s reporting to support his claim, though Trump has dismissed Wolff as an unreliable “third-rate reporter.” The Daily Beast, which also referenced the story, later retracted it following legal pressure.

Melania’s spokesperson reaffirmed her legal team’s efforts to demand retractions, pointing to her memoir Melania, in which she writes that she met Donald Trump at a 1998 Fashion Week party. Her legal team maintains that any alternate version of this story is defamatory and baseless.

Biden said he was open to a deposition involving the Trumps to clarify the matter but maintained, “I can only go by what people are saying.” He also offered the Trumps a platform to explain the situation if they chose to respond directly.

The controversy adds to Hunter Biden’s history of legal battles, including lawsuits related to the misuse of his laptop data and a dropped defamation case against Fox News over a graphic docuseries. Fox responded to one dropped case by calling it “nothing more than a politically motivated stunt.”