"There is other information relevant to the defense that is either classified or being suppressed by the government, not the least of which are the transcripts and recordings of the phone calls that supposedly underpin the charges against Mr. Flynn", the filing reads.
Flynn is awaiting sentencing after pleading guilty of lying to the FBI about conversations with Moscow’s former Ambassador to Washington, Sergei Kislyak, about prospects for lifting US sanctions on Russia.
"We must have access to that information to represent our client consistent with his constitutional rights and our ethical obligation", the filing continues.
The filing further says that Flynn’s cooperation with prosecutors had ended and that prosecutors have proposed dates for a sentencing hearing between 21-23 October or 1-15 November.
The filing is part of a status report filed with the US federal court in Washington.
After pleading guilty to lying to the FBI in December 2017, Flynn’s sentencing was delayed because he agreed to cooperate with the investigation by Special Counsel Robert Mueller of ties between Russia and the Trump campaign.
Prosecutors want to go ahead with sentencing now that Muller has completed his report, which found no collusion took place during the campaign.