WASHINGTON (AP) — Roger Stone, a longtime adviser and confidant of President Donald Trump, pleaded not guilty Tuesday to charges in the Russia investigation after a publicity-filled few days spent torching the probe as politically motivated.

The political operative and self-proclaimed dirty trickster appeared for his arraignment at the federal courthouse in Washington. He faces charges that he lied to lawmakers, engaged in witness tampering and obstructed a congressional investigation into possible coordination between Russia and Trump's 2016 presidential campaign.

Stone made no public statements as he arrived for the hearing in a black SUV. He waved to a small crowd of supporters chanting that he did nothing wrong and holding up glowing photos of him. And he largely ignored a group of protesters yelling "Lock him up" and carrying signs reading "dirty traitor."

Stone was arrested early Friday at his Florida home. He appeared in federal court in Washington amid new signals about special counsel Robert Mueller probe's endgame. Acting Attorney General Matthew Whitaker said Monday that the investigation is "close to being completed," although an exact timetable is unclear.

Mueller's continued interest in hearing from Stone aide Andrew Miller, who is fighting the grand jury subpoena, indicates the special counsel could be pursuing additional criminal charges against Stone or others related to WikiLeaks' release of hacked material during the 2016 election.

A self-described dirty trickster, Stone is the sixth Trump aide charged in Mueller's investigation. The indictment does not accuse Stone of coordinating with Russia or with WikiLeaks on the release of hacked Democratic emails. But it does allege that he misled lawmakers about his pursuit of those communications and interest in them. The anti-secrecy website published emails in the weeks before the 2016 presidential election that the U.S. says were stolen from Democrats by Russian operatives.

Stone, who has alleged without evidence that the FBI used "Gestapo tactics" in arresting him, said he did nothing more than exercise his First Amendment rights to drum up interest with voters about the WikiLeaks disclosures. He said he never discussed the issue with Trump.

"That's what I engaged in. It's called politics and they haven't criminalized it, at least not yet," Stone said Sunday on ABC's "This Week."

"All I did was take publicly available information and try to hype it to get it as much attention as possible, because I had a tip, the information was politically significant and that it would come in October," he added.

Tuesday's arraignment could inspire the same circus-like atmosphere that surrounded his Friday court appearance in Florida, where Stone emerged from the building in a blue polo shirt, flashed a Richard Nixon victory sign, predicted his vindication and vowed that he would not "bear false witness against the president, nor will I make up lies to ease the pressure on myself."

It's unclear whether Mueller's prosecutors will look to have Stone locked up pending trial or whether they will simply recommend conditions that would allow him to remain free on bond. It's also possible that U.S. Magistrate Deborah Robinson might impose a gag order to prevent Stone from discussing the case.

Associated Press writer Colleen Long contributed to this report.