A federal judge revoked bail for Paul Manafort, a former chairman of Donald Trump's presidential campaign, after government lawyers alleged that he had tried to contact potential witnesses in a criminal case.

Manafort pleaded not guilty to a superseding indictment in front of U.S. District Judge Amy Berman Jackson of the U.S. District Court for the District of Columbia. The latest indictment from special counsel Robert Mueller added witness tampering charges to earlier charges of money laundering and tax evasion.

After the judge's order revoking bail, Manafort was led away by federal court marshals, according to The Washington Post.

The special counsel, who is investigating alleged Russian interference in U.S. elections, is alleging that Manafort, whose firm worked for Ukraine for decades, engaged in illegal lobbying efforts and money laundering. Manafort has denied all the charges.

Manafort resigned from the Trump campaign after news outlets reported that he had allegedly received payments from Ukraine that had not been properly reported.

Speaking to reporters earlier on June 15, Trump emphasized that Manafort spent relatively little time with the campaign.

"[Manafort] worked for many other Republicans," the president said. "He worked for me, what, for 49 days or something? A very short period of time."

Prosecutors argued that the attempt to contact witnesses was in violation of the court's order confining Manafort to his home. Defense attorneys responded that the court's order was not clear, according to news reports.