Roger Stone, a longtime associate of President Donald Trump who was arrested Friday after being indicted on charges of obstruction, making false statements to Congress and witness tampering as part of special counsel Robert Mueller's probe, said Sunday that he would be honest with Mueller if he eventually ends up cooperating with his investigation.

Speaking with ABC News' "This Week," Stone was asked if there was "any chance you’ll cooperate with special counsel Robert Mueller if he asks?"

"You know, that’s a question I would have to — I have to determine after my attorneys have some discussion," Stone said. "If there’s wrongdoing by other people in the campaign that I know about, which I know of none, but if there is, I would certainly testify honestly."

"I’d also testify honestly about any other matter, including any communications with the president," he continued. "It’s true that we spoke on the phone, but those communications are political in nature, they’re benign, and there is — there is certainly no conspiracy with Russia."

A longtime GOP operative and self-described "dirty trickster," Stone had repeatedly denied colluding with WikiLeaks in the website's release of a trove of hacked Democratic emails in the lead-up to the 2016 presidential election.

Stone, 66, was arrested by federal agents in a pre-dawn raid Friday at his Fort Lauderdale, Florida, home. In his Sunday interview, he accused the government of using "Gestapo" tactics on him.

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The arrest came one day after a grand jury in the U.S. District Court for the District of Columbia indicted him on five counts of making false statements, one count of witness tampering and one count of obstruction as part of Mueller's probe into Russian election interference. He was released on $250,000 bond. Stone said he would "defeat" the charges in court.

"I will not testify against the president because I would have to bear false witness against him," he said Friday.

While the indictment did not accuse Stone of coordinating with the Russians, it does say Stone spoke with senior Trump campaign officials about WikiLeaks and "information it might have had that would be damaging to the Clinton Campaign." The indictment said that after WikiLeaks released stolen Democratic National Committee emails in July, a senior Trump campaign official was directed to contact Stone about possible future damaging releases, and Stone later told officials about potential future releases, the indictment alleges.

On Saturday night, Trump tweeted that Stone "didn't even work for me anywhere near the Election!" Stone's work in an official capacity for the campaign ended early in Trump's presidential bid, before the hacked emails came into play. In December, Trump tweeted out a comment Stone made promising to "never testify against Trump," which the president praised saying it was "nice" that "some people still have 'guts!'"

Stone told "This Week" that the president has never discussed a pardon with him, nor had he and Trump ever discussed WikiLeaks or its founder, Julian Assange. Stone added that Trump's Saturday night tweet — appearing to create distance between the two — was not of much concern to him.

"I never discussed these matters with the president, and everything that I did regarding trying to get as much public attention to the WikiLeaks disclosures among voters, among the media is — is constitutionally protected free speech," he said. "That's what I engaged in. It's called politics, and they haven’t criminalized it — at least not yet."

Responding to Stone's interview, former New Jersey Gov. Chris Christie — a Trump ally — told "This Week" that the indictment against Stone was substantial.

"He’s got a problem," Christie, a former U.S. attorney, said of Stone. "Because they’ve got all these e-mails and text messages that he created that tell a pretty clear story."

Christie added that if Stone were to go to trial, "he's in very, very grave danger."

"Everyone is presumed innocent ... and so is he," Christie said. "But the indictment I think is a pretty damning indictment."

House Intelligence Chairman Adam Schiff expressed similar sentiment in an interview on the same program, saying the indictment does not contain "ambiguous statements," but allegations that are "very detailed."

"And I think he’s going to need a much better defense than the one you just heard," he said.