Longtime Trump confidant Roger Stone said Sunday he is open to cooperating with special counsel Robert Mueller's federal Russia investigation.

"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 would also testify honestly about any other matter, including any communications with the president," Stone told ABC News' "This Week." "It’s true that we spoke on the phone, but those communications are political in nature, they’re benign, and there is certainly no conspiracy with Russia. The president’s right, there is no Russia collusion."

Stone, 66, has previously indicated his willingness to talk to federal investigators all the while claiming he will remain loyal to Trump. The former Nixon political operative and self-described political trickster said on Sunday that Trump had "absolutely, positively not" broached the possibility of pardoning him. He additionally said "zero" of his conversations with Trump have been in relation to Russia interference or the Mueller inquiry.

A grand jury impaneled for Mueller's investigation last week indicted Stone on five counts of lying to Congress, one count of witness tampering, and another count obstructing a congressional investigation. Stone was arrested in Florida on Friday and appeared in court later that day.

[More: 'FBI, open the door! FBI warrant!: Armed agents in riot gear arrested Roger Stone in pre-dawn raid]

The charges stem from Stone's September 2017 interview with the House Intelligence Committee, which was examining Russia's attempts to influence the 2016 election and the response by U.S. intelligence and law enforcement agencies. The testimony focused, in part, on WikiLeaks and its release of hacked material from the Democratic National Committee and Clinton campaign chairman John Podesta during the 2016 campaign.