The Justice Department is asking a judge to dismiss a lawsuit filed by Donald Trump's former presidential campaign chairman.

Paul Manafort was indicted in October in special counsel Robert Mueller's Russia investigation. A suit Manafort filed last month challenges the scope of Mueller's appointment and authority.

The government says in a court filing Friday that a judge should throw out that suit. Justice Department lawyers say federal courts are prohibited from interfering with ongoing criminal prosecutions — and that Mueller's been operating properly and not exceeded his authority.

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The department says if Manafort believes he's being unfairly prosecuted, then he can file a motion in his criminal case to seek to have it dismissed.

Manafort is one of four people charged so far in Mueller's investigation.

In the suit, Manafort has argued Deputy Attorney General Rod Rosenstein didn't have authority to appoint Mueller as special counsel, which occurred after Mr. Trump fired James Comey as FBI director. The complaint claims that the appointment was an "abuse of discretion" and therefore, he says that anything resulting from Mueller's investigation into Russia's meddling in the 2016 presidential election should be deemed null and void. The complaint then says that Mueller's investigation and the indictment against Manafort goes beyond the scope of his authority, and demands that Mueller "should be enjoined from further investigating any alleged conduct by Mr. Manafort that is unrelated to and predates his involvement with the Trump campaign…" It goes on to say that Manafort should be awarded injunctive relief.

Manafort and Rick Gates, Manafort's former business associate, were indicted by a federal grand jury in the investigation into Russian meddling in the U.S. election in October. Another Trump campaign aide, George Papadopoulos, pleaded guilty the same day to making false statements to the FBI. Toward the end of 2017, Mueller's investigation into Russian interference in the 2016 election was just heating up. Mr. Trump's former national security adviser, Michael Flynn, pleaded guilty to one count of lying to the FBI.

— CBS News' Rebecca Shabad contributed to this report