(CNN) Donald Trump is suing a former campaign aide for $10 million, alleging that the ex-staffer breached a confidentiality agreement.
The lawsuit injects more drama to the Trump campaign as rumors swirl about the Republican presumptive nominee's vice presidential pick.
Sam Nunberg, who was fired late last summer from the campaign after racially charged Facebook posts of his surfaced, is the former aide being sued. Nunberg's lawyer, Andrew Miltenberg, told CNN Wednesday that Nunberg is being accused of "violating certain confidentiality provisions by talking about Donald Trump after he was no longer associated with the campaign."
"It has to do with information within the campaign and relationships between the various people within the campaign," Miltenberg said, adding that he would not elaborate further.
Miltenberg told CNN Wednesday that the Trump camp had asked a judge for the arbitration to be sealed.
However, some of the exhibits in the suit were not sealed, including three news stories to back up its claim that Nunberg breached his confidentiality agreement. One is a New York Post report of two campaign staffers screaming at each other in the streets, and the others are Politico articles headlined "Fired Trump aide backs Ted Cruz" and "Trump campaign gets personal," which included quotes from Nunberg.
In Nunberg's affidavit obtained by CNN, Nunberg says he did not provide the New York Post with any information concerning "that embarrassing and lurid event" between Trump's then-campaign manager, Corey Lewandowski, and its current spokeswoman, Hope Hicks. Nunberg alleges that the Trump campaign is trying to "silence media coverage" of the relationship between Lewandowski and Hicks, calling it a "sordid and apparently illicit affair."
Nunberg also claims in the affidavit that he is being sued "in retaliation for my change of political opinion and the free exercise of my First Amendment right to abandon my political backing of Mr. Trump." (Nunberg endorsed Texas Sen. Ted Cruz after leaving the Trump campaign.)
Trump Organization General Counsel Alan Garten confirmed the lawsuit but declined to disclose additional details because the suit is "subject to arbitration."
On Wednesday night the Trump campaign issued a statement by Garten explaining the litigation.
"As is standard practice for all major businesses, organizations and other entities dealing with proprietary information, Mr. Trump requires employees to sign and adhere to strict confidentiality agreements," the statement said. "When the agreements are not adhered to he will enforce them to the full extent of the law, and Mr. Trump's litigation track record on such matters is outstanding. With regard to Mr. Nunberg, this agreement specifically calls for arbitration, and Mr. Nunberg is simply looking for free publicity using categorically false claims."
News of the lawsuit was first reported by The Associated Press.
Trump's attorneys filed the lawsuit Tuesday in New York Supreme Court.
Nunberg, through his association with longtime Trump political adviser Roger Stone, advised Trump amid his flirtation with a presidential run in 2012. And when Trump began preparing his 2016 bid, Nunberg was again at his side, making early preparations for a potential campaign.
But late last summer, racially charged posts that Nunberg posted on Facebook surfaced and the campaign fired him.
Since then, Nunberg has been fiercely critical of Trump and his campaign staff, particularly Lewandowski, who is now a CNN contributor.
The suit comes as Trump is preparing to select a vice presidential running mate later this week.