Roger Stone, longtime advisor to US President Trump, leaves the U.S. District Courthouse after his arraignment in Washington, United States on January 29, 2019.

A federal judge on Friday slapped a partial gag order on Roger Stone and lawyers for the longtime controversial Republican operative, barring them from making statements to the media and in public that risk prejudicing the case against him.

Judge Amy Berman Jackson also said barred Stone and his lawyers from making such statement as the enter and leave the U.S. District Court in Washington, D.C., courthouse because of the risk that they could taint potential jurors in his criminal case and make it difficult for the long-time friend of President Donald Trump to get a fair trial.

But the judge pointedly did not impose a full gag order on the notoriously verbose Stone.

That case was against Stone was lodged in late January by special counsel Robert Mueller. Jackson's partial gag order also applies to Mueller, whose prosecutors already have a practice of never publicly talking to reporters anywhere.

The self-admitted dirty trickster Stone, who was free on a $250,000 bond, is charged with witness tampering, obstruction of justice and making false statements to Congress.

Mueller says Stone lied to Congress about his alleged efforts to have WikiLeaks release material hacked by Russian agents from Democrats, including Hillary Clinton's campaign chairman, during the 2016 campaign that ended with Trump's victory.

Stone has pleaded not guilty.

In her order Friday, Jackson said: "Counsel for the parties and the witnesses must refrain from making statements to the media or in public settings that pose a substantial likelihood of material prejudice to this case."

"And all interested participants in the matter, including the parties, any potential witnesses, and counsel for the parties and the witnesses, must refrain, when they are entering or exiting the courthouse, or they are within the immediate vicinity of the courthouse, from making statements to the media or to the public that pose a substantial likelihood of material prejudice to this case or are intended to influence any juror, potential juror, judge, witness or court officer or interfere with the administration of justice."

Jackson added that she "has particular concerns about the potential impact of public statements made in the District of Columbia, directed at individuals who may be members of the venire from which the jury will be drawn."

The judge noted that "there will be no additional restrictions imposed on the defendant's public statements or appearances at this time, although this order may be amended in the future" if necessary.

Stone's lawyer Grant Smith's told NBC News, "As you can see in the order, Roger Stone is not in any way 'gagged' and the courthouse steps is a reasonable place for everyone to act with restraint and decorum."

A spokesman for Mueller declined to comment.

The special counsel is investigating Russian interference in the 2016 presidential election and possible collusion by the Trump campaign, as well as possible obstruction of justice by Trump himself. The president has denied any wrongdoing.