Paul Manafort is being held in solitary confinement while he awaits trial.

Manafort's lawyer said Thursday he was being held in his cell 23 hours per day to "guarantee his safety" and cannot adequately prepare for his upcoming trial later this month.

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Paul Manafort is being held in solitary confinement in a Virginia jail while he awaits trial, according to a document his lawyer filed Thursday.

Manafort's lawyer Kevin Downing said Manafort is being held for 23 hours a day because "the facility cannot otherwise guarantee his safety" and complained he cannot adequately prepare for his upcoming trial, which is slated for July 25.

Assistant special counsel Scott Meisler hit back with a reply also filed Thursday. In it, Meisler wrote the appeal notion should be denied, as Manafort's actions were "committed through covert corrupt persuasion" and that the terms of his sentence "are common to defendants incarcerated pending trial."

The filing also said Manafort has not taken any action to improve his confinement conditions.

Manafort, President Donald Trump's former campaign chairman, has been held in Virginia's Northern Neck Regional Jail since June 15, when a federal judge revoked his bail after learning that he and an associate, the former Russian intelligence operative Konstantin Kilimnik, tried to tamper with witness testimony in the investigation.

Manafort has pleaded not guilty to more than 20 charges in the special counsel Robert Mueller's Russia investigation, including tax and bank fraud, conspiracy, obstruction of justice, and failure to register as a foreign agent.

Trump tweeted in protest of Manafort's sentence last month.