WASHINGTON (CN) – A federal judge on Friday tossed out former Trump campaign manager Paul Manafort’s civil lawsuit challenging the authority of the special counsel who is investigating Russian interference in the 2016 presidential election.

Manafort had asked the court in his Jan. 3 lawsuit to dismiss the criminal charges pending against him in Washington, alleging that Acting Attorney General Rod Rosenstein’s special counsel appointment order failed to comply with Department of Justice regulations.

Manafort had also claimed that special counsel Robert Mueller exceeded his authority by indicting him for conspiracy, money laundering and failing to register as a foreign agent for lobbying work he did on behalf of a pro-Russian political party in Ukraine, since those matters did not relate to Russia’s interference in the 2016 election.

He later narrowed the claims, seeking only to bar future indictments by the special counsel, and asking the court to declare as invalid the provision of the appointment order that allows Mueller to pursue “any matters that arose or may arise directly from the investigation.”

But U.S. District Judge Amy Berman Jackson said that a civil case is an inappropriate way to challenge a prosecutor’s actions.

“It is a sound and well-established principle that a court should not exercise its equitable powers to interfere with or enjoin an ongoing criminal investigation when the defendant will have the opportunity to challenge any defects in the prosecution in the trial court or on direct appeal,” the 24-page ruling says.

Manafort’s civil case invoked the Administrative Procedure Act, which Jackson said requires him to lack another adequate remedy. But Manafort has an alternative, Jackson said – he can seek relief from the criminal case against him under the Federal Rules of Criminal Procedure.

Jackson noted Manafort’s acknowledgement that he can challenge any future prosecutions brought by Mueller under the appointment order individually.

“While a series of orders dismissing one indictment at a time is a different form of relief than a blanket order enjoining all future prosecutions, the remedies are certainly ‘of the same genre,'” the ruling says.

But Jackson also said Manafort failed to identify any impending harm that would justify enjoining the special counsel’s future prosecutorial activities.

“Since it is not clear at this point what actions, if any, the Special Counsel will take with respect to Manafort, and whether those future actions will be subject to attack for the same reasons set forth in the complaint, prudential considerations weigh against hearing an action to prohibit them now,” Jackson wrote.

Any issues Manafort has with Mueller can be taken up within his criminal case, she said.

The Office of Special Counsel declined to comment on the ruling. Manafort’s attorney Kevin Downing did not respond to an email seeking comment on the opinion.