Trump ally Roger Stone rejects Russia charges
Political strategist Roger Stone, and long-time ally of President Trump, has been charged with seven counts in the Mueller probe.
Mr Stone appeared in court in the city of Fort Lauderdale.
He later told journalists gathered outside he believed the investigation was politically motivated.
The indictment includes one count of obstruction of an official proceeding, five counts of false statements, and one count of witness-tampering.
The charges are linked to an alleged Russian-led hack into the emails of Democratic Party officials.
The information contained in the emails was released by Wikileaks during the 2016 US presidential election campaign.
CNN reports that FBI agents arrested Mr Stone in a pre-dawn raid on Friday. One pounded on the door and said, "FBI, open the door," the US cable network says.
After news of his old friend's arrest, President Donald Trump slammed the Russia investigation once again on Twitter, calling it the "Greatest Witch Hunt in the History of our Country!"