The federal judge overseeing the criminal case against former Trump campaign chairman Paul Manafort and his associate Rick Gates has issued a gag order limiting comments to the media and the public by lawyers, defendants and witnesses in the case.

U.S. District Court Judge Amy Berman Jackson's directive released Wednesday doesn't ban such statements outright, but prohibits any remarks that "pose a substantial likelihood of material prejudice to this case."

At a hearing last week, Jackson urged lawyers to make their arguments in court and "not on the courthouse steps." She also appeared to criticize a statement one of Manafort's lawyers made outside court calling the charges against his client "ridiculous."

"This is a criminal trial, and it's not a public relations campaign," the judge warned.