Washington (CNN) Special counsel Robert Mueller's team argued Thursday against a request by former Trump campaign chairman Paul Manafort's lawyers to release him from jail to better prepare for his trial, saying it's not necessary and shouldn't happen.

Though he may not be violent, Manafort's attempts to contact potential witnesses in his case and influence their testimony are indeed dangerous, the prosecutors argued.

Witness tampering "is no less damaging to the justice system when committed through covert corrupt persuasion than through overt violence," they wrote to the appellate court Thursday.

A panel of appellate judges in Washington, DC, is weighing whether Manafort should be released as he awaits trial. He has been in a cell akin to solitary confinement at Virginia's Northern Neck Regional Jail since June 15 after a judge in DC revoked his bail for allegedly contacting witnesses in his case.

He had been on house arrest since late October in Alexandria, Virginia, with a $10 million unsecured bond after the court had deemed him a flight risk. Mueller's legal team argues that the terms the judge set for Manafort's house arrest months ago -- that he not commit any crimes while awaiting trial -- was clear.

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