Robert Mueller accuses ex-Donald Trump aide of witness tampering

(Right) Robert Mueller, who is investigating alleged Russian election interference, said Paul Manafort (left) had contacted people related to his money laundering and tax fraud case. Pics/AFP

Former Trump campaign chairman Paul Manafort made several attempts to tamper with witnesses in his ongoing criminal cases, prosecutors said as they asked a federal judge to consider jailing him while he awaits trial.

In a court filing, prosecutors working for special counsel Robert Mueller wrote that Manafort and one of his associates "repeatedly" contacted two witnesses in an effort to influence their testimony.

The contacts occurred earlier this year, shortly after a grand jury returned a new indictment against Manafort. The filing marks the second time that Mueller's team has accused Manafort of violating a judge's order in the case. Last year, federal agents discovered that Manafort was attempting to ghostwrite an opinion piece in Ukraine even though he was under a gag order in the case.

In the latest court documents, prosecutors say that while he was under house arrest, Manafort and his associate attempted to get two witnesses to lie about the nature of lobbying and public relations work they carried out at Manafort's direction on behalf of Ukraine. However, Manafort has denied any wrongdoing and pleaded not guilty.