President Donald Trump’s former National Security Adviser Michael Flynn leaves the E. Barrett Prettyman U.S. Courthouse on June 24, 2019 in Washington, DC.

Former Trump national security advisor Michael Flynn is ready to be sentenced, federal prosecutors said Friday, but his lawyers are demanding more time and access to classified material.

"The case is not ready for sentencing," Flynn's lawyers, including the recently hired Sidney Powell, wrote in a joint status report filed in Washington district court.

Flynn's team argued that they have hundreds of thousands of documents to pore over as part of their review of the case and have been unable to acquire other information, including transcripts and recordings of phone conversations, "that is either classified or being suppressed by the government."

"We must have access to that information to represent our client consistently with his constitutional rights and our ethical obligations," they wrote.

The federal prosecutors disagreed: "The government is not aware of any classified information that requires disclosures to the defendant or his counsel."

Prosecutors suggested the court schedule another status conference in light of the impasse. They offered four dates in September; Flynn's team said they would not be available then.

Later on Friday, Judge Emmet Sullivan scheduled a status conference for the morning of Sept. 10.

Flynn had pleaded guilty to lying to the FBI about his contacts with former Russian Ambassador Sergey Kislyak in the weeks before President Donald Trump's inauguration. He was supposed to be sentenced in December but he accepted Judge Emmet Sullivan's offer for a delay until his cooperation was complete. Sullivan excoriated him at that hearing, saying "arguably, you sold your country out."

Flynn had originally been charged as part of special counsel Robert Mueller's investigation of Russia's election interference and possible coordination with Trump's 2016 presidential campaign. He had also been seen as a potential witness in the trial of Bijan Rafiekian and Kamil Alptekin, Flynn's former business partners, who were accused of illegally lobbying on behalf of the government of Turkey.

"Flynn's cooperation is complete," his attorneys said in the report. He "cooperated extensively" with Mueller's office and with prosecutors in the Rafiekian case, they said. "This cost Mr. Flynn more than 100 hours of his time and hundreds of thousands of dollars in additional legal fees."

But they asked the judge to schedule another status report in 90 days.

The government, however, asked Sullivan to move forward with the sentencing schedule. They proposed a sentencing hearing sometime in late October or the first half of November.

"The government is not aware of any issues that require the Court's resolution prior to sentencing," they wrote in the joint report.

Flynn hired Powell in June — a move that raised questions from some experts about whether the retired Army lieutenant general was angling for a pardon from Trump.

Powell, a vocal supporter of Trump, had previously urged Flynn to withdraw his guilty plea. After she was hired to represent Flynn in the case, however, she reportedly said that Flynn would continue to cooperate with the government.