Gen. Michael Flynn, former national security adviser to US President Donald Trump, leaves Federal Court on December 1, 2017 in Washington, DC. Brendan Smialowski | AFP | Getty Images

Special counsel Robert Mueller on Friday urged a federal judge to reject an attempt by President Donald Trump's former national security advisor Michael Flynn "to minimize the seriousness" of his crime days before his sentencing date. But Flynn should still receive a light sentence, Mueller added. Flynn had pleaded guilty last year to lying to the FBI about his contacts with the Russian ambassador to the U.S. In a court filing this week, Flynn's lawyers noted that he was interviewed without a lawyer present and was not told in advance that lying to the FBI was a crime. The special counsel said in its filing Friday afternoon that "nothing about the way the interview was arranged or conducted caused the defendant to make false statements to the FBI." The filing said that the agents who questioned Flynn gave him multiple opportunities to correct false statements he made, and told him in advance of the meeting that the questions had to do with his contacts with the Russian ambassador. "The interview was voluntary, and lacked any indicia of coercion," according to Mueller. The filing also noted that Flynn had repeatedly lied about his communications with the Russian official two weeks before sitting down with the FBI.

The special counsel's filing came a day after the judge presiding over Flynn's case ordered the special counsel to submit documents related to Flynn's interview with the FBI. Two of those documents, known as "302s," are included in the government's Friday afternoon filing, though both are heavily redacted. The order fueled speculation that U.S. District Judge Emmet Sullivan was looking for more information about the conditions surrounding Flynn's January 2017 interview with the FBI. In their sentencing memo filed earlier this week, Flynn's lawyers cited ex-FBI Deputy Director Andrew McCabe, who said he told Flynn at the time of that interview that "the quickest way to get this done was" for him to speak with agents by himself without a lawyer present. Flynn's team also said the agents didn't provide him "with a warning of the penalties" for lying to the FBI. The new details about Flynn's interview with investigators incensed some of his supporters, who argue that the FBI engaged in tactics akin to "entrapment." Trump weighed in, too, telling reporters Thursday that "it's a great thing that the judge is looking into that situation" by ordering Mueller's team to turn over more documents about the interview. Other legal experts dispute that conclusion, however. David Weinstein, a defense attorney and former federal prosecutor, said that while it's possible that some "trickery" by the FBI may have been at play, the agents were under no requirement to read Flynn his rights before questioning him. "My takeaway: He was sitting down with FBI agents. He should be prepared to tell the truth," Weinstein said. Mueller made the same point in the court filing Friday. A veteran U.S. official such as Flynn "does not need to be warned it is a crime to lie to federal agents to know the importance of telling them the truth," the special counsel said. Flynn was "undoubtedly was aware, in light of his 'many years' working with the FBI, that lying to the FBI carries serious consequences," the filing added. The retired lieutenant general's sentencing hearing is set for next Tuesday at 11 a.m. ET in Washington, D.C. federal court. In prior sentencing documents, Flynn's lawyers and the special counsel had both recommended a light sentence for the highly decorated U.S. Army veteran.