Updated 7.10pm
Roger Stone, a longtime advisor to Donald Trump, was arrested Friday on charges relating to the investigation into possible collusion between the president's election campaign and Russia.
Stone was taken into custody by heavily armed police in a predawn raid at his home in Fort Lauderdale, Florida after an indictment was unsealed in Washington by Special Counsel Robert Mueller.
He appeared in Fort Lauderdale court in handcuffs charged with seven counts, including obstruction of justice, making false statements to Congress and witness tampering.
The cuffs were removed from the 66-year-old veteran Republican political consultant as he posted $250,000 bail.
"I will plead not guilty to these charges. I will defeat them in court. I believe this is a politically-motivated investigation," Stone said as he emerged from court.
His statement was interrupted by chants from onlookers of "lock him up!" -- a caustic reference to the frequent refrain used during the campaign to rally Trump's base against rival Hillary Clinton.
"I will not testify against the president, because I would have to bear false witness against him," Stone added.
His lawyer Grant Smith had earlier told the South Florida Sentinel that Stone was "absolutely innocent" of the charges.
The White House rejected suggestions that the noose was getting tighter around Trump, who has denied any collusion with Russia.
"This has nothing to do with the president and certainly nothing to do with the White House," spokeswoman Sarah Sanders told CNN.
Trump's lawyer Jay Sekulow added in a statement that the indictment did not allege Russian collusion by Stone or anyone else.
Contacts with WikiLeaks
The indictment, which arose from Stone's statements in testimony to the House Intelligence Committee in 2017, involved his 2016 communications with Julian Assange, the founder of WikiLeaks, which published material stolen by Russian hackers from the Clinton campaign.
The indictment made ample mention of communications between Stone and unnamed "senior officials" of the Trump election campaign about his communications with WikiLeaks and releases of the stolen materials.
Tantalizingly, the indictment says that after WikiLeaks' July 22, 2016 release of stolen Democratic emails, "a senior Trump Campaign official was directed to contact Stone about any additional releases and what other damaging information" WikiLeaks might have on Clinton.
Adam Schiff, who chairs the House Intelligence Committee, said that was a key revelation.
"Our committee will be eager to learn just who directed a senior campaign official to contact Stone about additional damaging information held by WikiLeaks, one of the publishing arms of Russian government hackers," Schiff said.
But neither Stone nor other campaign officials have been charged by Mueller with conspiring with Assange or Russian officials.
It was the first indictment in months by the special prosecutor probing Russian efforts to influence the election and whether Trump and his aides tried to obstruct justice.
Stone, who launched his career as a campaign aide to Richard Nixon and has a tattoo on his back of the first US president to resign from office, has spent decades advising various US political campaigns.
He was one of the first members of Trump's team when the billionaire real estate magnate formally announced he was seeking office, but he left months later.
The two men, however, remained in close contact, with the indictment saying that Stone "maintained regular contact with and publicly supported the Trump Campaign through the 2016 election."
Ready to testify?
Stone's indictment has been long expected, and according to his lawyer he has not been interviewed by Mueller's team, suggesting the veteran prosecutor does not expect Stone to provide evidence against Trump or others.
Both Trump and Stone have labeled the Mueller probe a politicized "witch hunt".
However, with Stone's arrest, Mueller has now indicted 34 individuals, including former top Trump aides Paul Manafort, who chaired the 2016 campaign; ex-national security advisor Michael Flynn, and Trump's former personal lawyer Michael Cohen.
Stone has insisted that he would never testify against Trump.
"There's no circumstance under which I would testify against the president," he told ABC's "This Week" in December -- to which Trump responded in a tweet: "Nice to know that some people still have 'guts!'"